V4L/DVB (7880): saa7134: remove explicit GPIO initialization

This causes a problem with the audio mute on some cards and is done
implictly in the audio initialization code.

Signed-off-by: Hartmut Hackmann <hartmut.hackmann@t-online.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>