[ARM] 3658/1: S3C244X: Change usb-gadget name to s3c2440-usbgadget

Patch from Ben Dooks

The S3C2440 and S3C2442 have an extended USB gadget
controller, so re-name the platform device to inform
the driver that it needs to change some parameters

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>