[media] drxk: Fix debug printks

This patch partially reverts 0fb220f2. What happened is
that the conversion of debug messages to use pr_debug() was a
bad idea, because one needing to debug would need to both
enable debug level via a modprobe parameter, and then to
enable the dynamic printk's.

So, for now, let's use printk() directly at dprintk().

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