[media] rc-core: split dev->s_filter

Overloading dev->s_filter to do two different functions (set wakeup filters
and generic hardware filters) makes it impossible to tell what the
hardware actually supports, so create a separate dev->s_wakeup_filter and
make the distinction explicit.

Signed-off-by: David Härdeman <david@hardeman.nu>
Acked-by: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>