USB HID: handle multi-interface devices for Apple macbook pro properly

Some HID devices by Apple have both keyboard and mouse interfaces; the
keyboard interface is handled by usbhid, but the mouse (really
touchpad) interface must be handled by the separate 'appletouch'
driver.  Using HID_QUIRK_IGNORE will make hiddev ignore both
interfaces, therefore a new quirk flag to ignore only the mouse
interface is required.

Signed-off-by: Soeren Sonnenburg <kernel@nn7.de>
Signed-off-by: Sergey Vlasov <vsu@altlinux.ru>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>