usb: gadget: Convert drivers to use module_usb_composite_driver()

Use the module_usb_composite_driver() macro where applicable to
eliminate the module_init/module_exit boilerplate in USB gadget composite
drivers.

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Felipe Balbi <balbi@ti.com>
diff --git a/drivers/usb/gadget/ether.c b/drivers/usb/gadget/ether.c
index c1c113e..c5fdc61 100644
--- a/drivers/usb/gadget/ether.c
+++ b/drivers/usb/gadget/ether.c
@@ -475,18 +475,8 @@
 	.unbind		= __exit_p(eth_unbind),
 };
 
+module_usb_composite_driver(eth_driver);
+
 MODULE_DESCRIPTION(PREFIX DRIVER_DESC);
 MODULE_AUTHOR("David Brownell, Benedikt Spanger");
 MODULE_LICENSE("GPL");
-
-static int __init init(void)
-{
-	return usb_composite_probe(&eth_driver);
-}
-module_init(init);
-
-static void __exit cleanup(void)
-{
-	usb_composite_unregister(&eth_driver);
-}
-module_exit(cleanup);