[media] mxl111sf: don't redefine pr_err/info/debug

Remove the silly redefines of pr_err/info/debug.
This improves readability and it also gets rid of a bunch of warnings when
compiling this driver for older kernels using the compatibility media_build
system.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>