[media] media: Use pr_info not homegrown pr_reg macro

No need to duplicate normal kernel logging capabilities.

Add pr_fmt and convert pr_reg to pr_info.
Remove pr_reg macros.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>