HID: Add suport for the brightness control keys on HP keyboards

The keys are found on the keyboards bundled with HP All-In-One machines
with USB VID/PID of 04ca:004d and 04f2:1061.

Signed-off-by: Keng-Yu Lin <kengyu@canonical.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>