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/composite.c b/drivers/usb/gadget/composite.c
index 717de39..a3009bf 100644
--- a/drivers/usb/gadget/composite.c
+++ b/drivers/usb/gadget/composite.c
@@ -1213,7 +1213,6 @@
 static struct usb_gadget_driver composite_driver = {
 	.speed		= USB_SPEED_HIGH,
 
-	.bind		= composite_bind,
 	.unbind		= composite_unbind,
 
 	.setup		= composite_setup,
@@ -1255,7 +1254,7 @@
 	composite_driver.driver.name = driver->name;
 	composite = driver;
 
-	return usb_gadget_register_driver(&composite_driver);
+	return usb_gadget_probe_driver(&composite_driver, composite_bind);
 }
 
 /**