[media] rc: raw decoder for keymap protocol is not loaded on register

[media] rc: raw decoder for keymap protocol is not loaded on register

When the protocol is set via the sysfs protocols attribute, the
decoder is loaded. However, when it is not when a device is first
plugged in or registered.

Fixes: acc1c3c ("[media] media: rc: load decoder modules on-demand")
Signed-off-by: Sean Young <sean@mess.org>
Cc: <stable@vger.kernel.org> # v4.5+
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>