[media] rc-core: remove the LIRC "protocol"

The LIRC protocol was always a bad fit and if we're ever going to expose
protocol numbers in a user-space API, it'd be better to get rid of the
LIRC "protocol" first.

The sysfs API is kept backwards compatible by always listing the lirc
protocol as present and enabled.

Signed-off-by: David Härdeman <david@hardeman.nu>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>