media: rc: no need to announce major number

Since commit a60d64b1 ("media: lirc: lirc interface should not be
a raw decoder"), the message in the documentation is incorrect as the
module name is rc_core, not lirc_dev. Since the message is not useful,
just make the message debug and remove it from the documentation.

Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>