[media] af9015: RC fixes and improvements

Read all remote	controller registers at	once to	reduce USB remote polling traffic.
Use .rc_codes() to disable / enable remote polling instead of .rc_query().

Signed-off-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>