blk: Introduce IF_TYPE_VIRTIO

This adds a new block interface type for VirtIO block devices.

Signed-off-by: Tuomas Tynkkynen <tuomas.tynkkynen@iki.fi>
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/block/blk-uclass.c b/drivers/block/blk-uclass.c
index 76ee3db..65a766e 100644
--- a/drivers/block/blk-uclass.c
+++ b/drivers/block/blk-uclass.c
@@ -23,6 +23,7 @@
 	[IF_TYPE_HOST]		= "host",
 	[IF_TYPE_NVME]		= "nvme",
 	[IF_TYPE_EFI]		= "efi",
+	[IF_TYPE_VIRTIO]	= "virtio",
 };
 
 static enum uclass_id if_type_uclass_id[IF_TYPE_COUNT] = {
@@ -37,6 +38,7 @@
 	[IF_TYPE_HOST]		= UCLASS_ROOT,
 	[IF_TYPE_NVME]		= UCLASS_NVME,
 	[IF_TYPE_EFI]		= UCLASS_EFI,
+	[IF_TYPE_VIRTIO]	= UCLASS_VIRTIO,
 };
 
 static enum if_type if_typename_to_iftype(const char *if_typename)