[media] rc-main: split setup and unregister functions

Move the input device allocation, map and protocol handling to
different functions.

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