media: lirc: remove last remnants of lirc kapi

rc-core has replaced the lirc kapi many years ago, and now with the last
driver ported to rc-core, we can finally remove it.

Note this has no effect on userspace.

All future IR drivers should use the rc-core api.

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