blk: Switch over to using uclass IDs

We currently have an if_type (interface type) and a uclass id. These are
closely related and we don't need to have both.

Drop the if_type values and use the uclass ones instead.

Maintain the existing, subtle, one-way conversion between UCLASS_USB and
UCLASS_MASS_STORAGE for now, and add a comment.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/cmd/bcb.c b/cmd/bcb.c
index 1bbd1fa..8b87aa0 100644
--- a/cmd/bcb.c
+++ b/cmd/bcb.c
@@ -122,7 +122,7 @@
 	char *endp;
 	int part, ret;
 
-	desc = blk_get_devnum_by_type(IF_TYPE_MMC, devnum);
+	desc = blk_get_devnum_by_type(UCLASS_MMC, devnum);
 	if (!desc) {
 		ret = -ENODEV;
 		goto err_read_fail;
@@ -287,7 +287,7 @@
 	u64 cnt;
 	int ret;
 
-	desc = blk_get_devnum_by_type(IF_TYPE_MMC, bcb_dev);
+	desc = blk_get_devnum_by_type(UCLASS_MMC, bcb_dev);
 	if (!desc) {
 		ret = -ENODEV;
 		goto err;
diff --git a/cmd/ide.c b/cmd/ide.c
index b78c38e..6739f0b 100644
--- a/cmd/ide.c
+++ b/cmd/ide.c
@@ -37,7 +37,7 @@
 		}
 	}
 
-	return blk_common_cmd(argc, argv, IF_TYPE_IDE, &curr_device);
+	return blk_common_cmd(argc, argv, UCLASS_IDE, &curr_device);
 }
 
 int do_diskboot(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
diff --git a/cmd/mmc.c b/cmd/mmc.c
index 7bd4cd9..0f1f4e0 100644
--- a/cmd/mmc.c
+++ b/cmd/mmc.c
@@ -331,13 +331,13 @@
 #else
 	original_part = mmc_get_blk_desc(mmc)->hwpart;
 #endif
-	if (blk_select_hwpart_devnum(IF_TYPE_MMC, curr_device, MMC_PART_RPMB) !=
+	if (blk_select_hwpart_devnum(UCLASS_MMC, curr_device, MMC_PART_RPMB) !=
 	    0)
 		return CMD_RET_FAILURE;
 	ret = cp->cmd(cmdtp, flag, argc, argv);
 
 	/* Return to original partition */
-	if (blk_select_hwpart_devnum(IF_TYPE_MMC, curr_device, original_part) !=
+	if (blk_select_hwpart_devnum(UCLASS_MMC, curr_device, original_part) !=
 	    0)
 		return CMD_RET_FAILURE;
 	return ret;
@@ -530,7 +530,7 @@
 	if (!mmc)
 		return CMD_RET_FAILURE;
 
-	mmc_dev = blk_get_devnum_by_type(IF_TYPE_MMC, curr_device);
+	mmc_dev = blk_get_devnum_by_type(UCLASS_MMC, curr_device);
 	if (mmc_dev != NULL && mmc_dev->type != DEV_TYPE_UNKNOWN) {
 		part_print(mmc_dev);
 		return CMD_RET_SUCCESS;
@@ -580,7 +580,7 @@
 	if (!mmc)
 		return CMD_RET_FAILURE;
 
-	ret = blk_select_hwpart_devnum(IF_TYPE_MMC, dev, part);
+	ret = blk_select_hwpart_devnum(UCLASS_MMC, dev, part);
 	printf("switch to partitions #%d, %s\n",
 	       part, (!ret) ? "OK" : "ERROR");
 	if (ret)
diff --git a/cmd/mvebu/bubt.c b/cmd/mvebu/bubt.c
index 2136af6..825d4be 100644
--- a/cmd/mvebu/bubt.c
+++ b/cmd/mvebu/bubt.c
@@ -412,7 +412,7 @@
 	}
 
 	/* Try to recognize storage devices immediately */
-	blk_first_device(IF_TYPE_USB, &dev);
+	blk_first_device(UCLASS_USB, &dev);
 	if (!dev) {
 		printf("Error: USB storage device not found\n");
 		return 0;
diff --git a/cmd/nvme.c b/cmd/nvme.c
index e715c57..09d5f43 100644
--- a/cmd/nvme.c
+++ b/cmd/nvme.c
@@ -28,7 +28,7 @@
 		if (strncmp(argv[1], "deta", 4) == 0) {
 			struct udevice *udev;
 
-			ret = blk_get_device(IF_TYPE_NVME, nvme_curr_dev,
+			ret = blk_get_device(UCLASS_NVME, nvme_curr_dev,
 					     &udev);
 			if (ret < 0)
 				return CMD_RET_FAILURE;
@@ -39,7 +39,7 @@
 		}
 	}
 
-	return blk_common_cmd(argc, argv, IF_TYPE_NVME, &nvme_curr_dev);
+	return blk_common_cmd(argc, argv, UCLASS_NVME, &nvme_curr_dev);
 }
 
 U_BOOT_CMD(
diff --git a/cmd/pvblock.c b/cmd/pvblock.c
index 56ce8b1..1b604c3 100644
--- a/cmd/pvblock.c
+++ b/cmd/pvblock.c
@@ -14,7 +14,7 @@
 
 int do_pvblock(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
 {
-	return blk_common_cmd(argc, argv, IF_TYPE_PVBLOCK,
+	return blk_common_cmd(argc, argv, UCLASS_PVBLOCK,
 			      &pvblock_curr_device);
 }
 
diff --git a/cmd/sata.c b/cmd/sata.c
index 76da190..9c9fe11 100644
--- a/cmd/sata.c
+++ b/cmd/sata.c
@@ -27,7 +27,7 @@
 	struct udevice *dev;
 	int rc;
 
-	blk_unbind_all(IF_TYPE_SATA);
+	blk_unbind_all(UCLASS_AHCI);
 
 	rc = uclass_find_device(UCLASS_AHCI, devnum, &dev);
 	if (!rc && !dev)
@@ -111,7 +111,7 @@
 		sata_curr_device = 0;
 	}
 
-	return blk_common_cmd(argc, argv, IF_TYPE_SATA, &sata_curr_device);
+	return blk_common_cmd(argc, argv, UCLASS_AHCI, &sata_curr_device);
 }
 
 U_BOOT_CMD(
diff --git a/cmd/scsi.c b/cmd/scsi.c
index 5f710d2..4549995 100644
--- a/cmd/scsi.c
+++ b/cmd/scsi.c
@@ -50,7 +50,7 @@
 		}
 	}
 
-	return blk_common_cmd(argc, argv, IF_TYPE_SCSI, &scsi_curr_dev);
+	return blk_common_cmd(argc, argv, UCLASS_SCSI, &scsi_curr_dev);
 }
 
 U_BOOT_CMD(
diff --git a/cmd/usb.c b/cmd/usb.c
index 3d87376..2ba0569 100644
--- a/cmd/usb.c
+++ b/cmd/usb.c
@@ -719,7 +719,7 @@
 	if (strncmp(argv[1], "stor", 4) == 0)
 		return usb_stor_info();
 
-	return blk_common_cmd(argc, argv, IF_TYPE_USB, &usb_stor_curr_dev);
+	return blk_common_cmd(argc, argv, UCLASS_USB, &usb_stor_curr_dev);
 #else
 	return CMD_RET_USAGE;
 #endif /* CONFIG_USB_STORAGE */
diff --git a/cmd/virtio.c b/cmd/virtio.c
index ea3ed2e..ec87d4f 100644
--- a/cmd/virtio.c
+++ b/cmd/virtio.c
@@ -40,7 +40,7 @@
 		return CMD_RET_SUCCESS;
 	}
 
-	return blk_common_cmd(argc, argv, IF_TYPE_VIRTIO, &virtio_curr_dev);
+	return blk_common_cmd(argc, argv, UCLASS_VIRTIO, &virtio_curr_dev);
 }
 
 U_BOOT_CMD(