media: rc: some events are dropped by userspace

libevdev (which is used by libinput) gets a list of keycodes from the
input device on creation. Any events with keycodes which are not in this
list are silently dropped. So, set all keycodes on device creation since
we do not know which will be used if the keymap changes.

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