[media] media: rc-core: simplify logging in rc_register_device

Simplify the logging.

I had some doubts about using the elvis operator as it's GNU extension.
However GNU extensions are explicitely allowed and this operator is
used at several places in the kernel code.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>