usb: s/CONFIG_DM_USB/CONFIG_IS_ENABLED(DM_USB)/

This allows to disable the USB driver model in SPL because it checks
the CONFIG_SPL_DM_USB variable for SPL builds. Nothing changes for
regular non-SPL builds.

Signed-off-by: Sven Schwermer <sven@svenschwermer.de>
diff --git a/drivers/usb/gadget/ci_udc.c b/drivers/usb/gadget/ci_udc.c
index 0a84f68..bd596ce 100644
--- a/drivers/usb/gadget/ci_udc.c
+++ b/drivers/usb/gadget/ci_udc.c
@@ -1015,7 +1015,7 @@
 	if (driver->speed != USB_SPEED_FULL && driver->speed != USB_SPEED_HIGH)
 		return -EINVAL;
 
-#ifdef CONFIG_DM_USB
+#if CONFIG_IS_ENABLED(DM_USB)
 	ret = usb_setup_ehci_gadget(&controller.ctrl);
 #else
 	ret = usb_lowlevel_init(0, USB_INIT_DEVICE, (void **)&controller.ctrl);
diff --git a/drivers/usb/gadget/ether.c b/drivers/usb/gadget/ether.c
index 90ef1f0..193583b 100644
--- a/drivers/usb/gadget/ether.c
+++ b/drivers/usb/gadget/ether.c
@@ -100,7 +100,7 @@
 	struct usb_gadget	*gadget;
 	struct usb_request	*req;		/* for control responses */
 	struct usb_request	*stat_req;	/* for cdc & rndis status */
-#ifdef CONFIG_DM_USB
+#if CONFIG_IS_ENABLED(DM_USB)
 	struct udevice		*usb_udev;
 #endif
 
@@ -2337,7 +2337,7 @@
 
 /*-------------------------------------------------------------------------*/
 
-#ifdef CONFIG_DM_USB
+#if CONFIG_IS_ENABLED(DM_USB)
 int dm_usb_init(struct eth_dev *e_dev)
 {
 	struct udevice *dev = NULL;
@@ -2362,7 +2362,7 @@
 	unsigned long ts;
 	unsigned long timeout = USB_CONNECT_TIMEOUT;
 
-#ifdef CONFIG_DM_USB
+#if CONFIG_IS_ENABLED(DM_USB)
 	if (dm_usb_init(dev)) {
 		pr_err("USB ether not found\n");
 		return -ENODEV;
@@ -2541,7 +2541,7 @@
 	}
 
 	usb_gadget_unregister_driver(&priv->eth_driver);
-#ifndef CONFIG_DM_USB
+#if !CONFIG_IS_ENABLED(DM_USB)
 	board_usb_cleanup(0, USB_INIT_DEVICE);
 #endif
 }