[media] saa7134: add vidioc_querystd

Signed-off-by: Mikhail Domrachev <mihail.domrychev@comexp.ru>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>