media: pvrusb2: replace `printk` with `pr_*`

Replace calls to `printk` with the appropriate `pr_*`
macro.

Signed-off-by: Dafna Hirschfeld <dafna3@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>