[media] rc: lirc keymap no longer makes any sense

The lirc keymap existed once upon a time to select the lirc protocol.
Since '275ddb40 [media] rc-core: remove the LIRC "protocol"', IR is
always passed to the lirc decoder so this keymap is no longer needed.

Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>