V4L/DVB (11762): dvb-ttpci: Fixed return code of av7110_av_start_play

av7110_av_start_play() should return 0 on success.

Signed-off-by: Oliver Endriss <o.endriss@gmx.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>