[media] cx88: don't declare restart_video_queue if not used

While compiled on alpha, got this error:
	drivers/media/pci/cx88/cx88-video.c:415:12: warning: 'restart_video_queue' defined but not used [-Wunused-function]

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