This patch removes the global variable composite in composite.c.
The private data which was saved there is now passed via an additional
argument to the bind() function in struct usb_gadget_driver.

Only the "old-style" UDC drivers have to be touched here, new style are
doing it right because this change is made in udc-core.
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Felipe Balbi <balbi@ti.com>