USB: gadget: amd5536udc.c: fix error path

In function udc_probe() call put_device() when device_register() fails.

Signed-off-by: Rahul Ruikar <rahul.ruikar@gmail.com>
Acked-by: Thomas Dahlmann <dahlmann.thomas@arcor.de>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>