HID: uHID: implement .raw_request

uHID is missing a SET_REPORT protocol implementation, but as
.hid_get_raw_report() as been removed from struct hid_device,
there were no means to access GET_REPORT in uhid.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Reviewed-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>