[media] v4l2-ioctl.c: always copy G/S_EDID result

The VIDIOC_G/S_EDID ioctls can return valid data even if an error is returned.

Mark those ioctls accordingly. Rather than using an explicit 'if' to check for the
ioctl (as was done until now for VIDIOC_QUERY_DV_TIMINGS) just set a new flag in the
v4l2_ioctls array.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>