media: rc: read out of bounds if bpf reports high protocol number

The repeat period is read from a static array. If a keydown event is
reported from bpf with a high protocol number, we read out of bounds. This
is unlikely to end up with a reasonable repeat period at the best of times,
in which case no timely key up event is generated.

Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>