usb gadget: fix platform driver hotplug/coldplug

Since 43cc71eed1250755986da4c0f9898f9a635cb3bf, the platform modalias is
prefixed with "platform:".  Add MODULE_ALIAS() to the hotpluggable usb
peripheral drivers, to re-eable module auto loading.

[dbrownell@users.sourceforge.net: registration fixes]
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/usb/gadget/fsl_usb2_udc.c b/drivers/usb/gadget/fsl_usb2_udc.c
index 63e8fa3..254012a 100644
--- a/drivers/usb/gadget/fsl_usb2_udc.c
+++ b/drivers/usb/gadget/fsl_usb2_udc.c
@@ -2475,3 +2475,4 @@
 MODULE_DESCRIPTION(DRIVER_DESC);
 MODULE_AUTHOR(DRIVER_AUTHOR);
 MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:fsl-usb2-udc");