[media] staging: media: as102: replace custom dprintk() with dev_dbg()

remove dprintk() and replace it with dev_dbg() or pr_debug()
in order to use the common kernel coding style.

Signed-off-by: Martin Kepplinger <martink@posteo.de>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>