usb gadget: don't save bind callback in struct usb_gadget_driver

To accomplish this the function to register a gadget driver takes the bind
function as a second argument.  To make things clearer rename the function
to resemble platform_driver_probe.

This fixes many section mismatches like

	WARNING: drivers/usb/gadget/g_printer.o(.data+0xc): Section mismatch in
	reference from the variable printer_driver to the function
	.init.text:printer_bind()
	The variable printer_driver references
	the function __init printer_bind()

All callers are fixed.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
[m.nazarewicz@samsung.com: added dbgp]
Signed-off-by: Michał Nazarewicz <m.nazarewicz@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/gadget/dbgp.c b/drivers/usb/gadget/dbgp.c
index abe4a2e..e5ac8a3 100644
--- a/drivers/usb/gadget/dbgp.c
+++ b/drivers/usb/gadget/dbgp.c
@@ -403,7 +403,6 @@
 static struct usb_gadget_driver dbgp_driver = {
 	.function = "dbgp",
 	.speed = USB_SPEED_HIGH,
-	.bind = dbgp_bind,
 	.unbind = dbgp_unbind,
 	.setup = dbgp_setup,
 	.disconnect = dbgp_disconnect,
@@ -415,7 +414,7 @@
 
 static int __init dbgp_init(void)
 {
-	return usb_gadget_register_driver(&dbgp_driver);
+	return usb_gadget_probe_driver(&dbgp_driver, dbgp_bind);
 }
 
 static void __exit dbgp_exit(void)