[media] fsl_viu: add VIDIOC_QUERYSTD and VIDIOC_G_STD support

VIDIOC_QUERYSTD and VIDIOC_G_STD ioctls are currently not
supported in the FSL VIU driver. The decoder subdevice
driver saa7115 extended by previous patch supports QUERYSTD
for saa711x, so we add the appropriate ioctls to the VIU
driver to be able to determine the video input's standard.

Signed-off-by: Anatolij Gustschin <agust@denx.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>