media: rc: move ir-lirc-codec.c contents into lirc_dev.c

Since removing the lirc kapi, ir-lirc-codec.c only contains lirc fops
so the file name is no longer correct. By moving its content into
lirc_dev.c the ugly extern struct lirc_fops is not longer needed,
and everything lirc related is in one file.

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