[media] rc: img-ir: add base driver

Add base driver for the ImgTec Infrared decoder block. The driver is
split into separate components for raw (software) decode and hardware
decoder which are in following commits.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>