[media] dvb-usb.h function rc5_scan

The function "rc5_scan" in "dvb_usb.h" is returning invalid value.
The value should be returned "u16" but is returning "u8".

See example below in "drivers/media/dvb/dvb-usb/opera1.c":

        send_key = (send_key & 0xffff) | 0x0100;

        for (i = 0; i < ARRAY_SIZE(rc_map_opera1_table); i++) {
            if (rc5_scan(&rc_map_opera1_table[i]) == (send_key & 0xffff)) {
                *state = REMOTE_KEY_PRESSED;
                *event = rc_map_opera1_table[i].keycode;
                opst->last_key_pressed =
                    rc_map_opera1_table[i].keycode;
                break;
            }
            opst->last_key_pressed = 0;
        }

Signed-off-by: Manoel Pinheiro <pinusdtv@hotmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>