[media] dvbsky: clean logging

dev_err includes the function name in the log printout, so there is no need to include it manually. While here, fix a small grammatical error in the i2c error message.

Signed-off-by: Olli Salonen <olli.salonen@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>