USB: properly pad out usb_device_id.driver_info

On some systems, struct usb_device_id doesn't align properly due to the
recent changes in it.  So pad out the driver_info field to align on a
boundry that systems can handle it.

Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Bjørn Mork <bjorn@mork.no>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>