media: v4l2-compat-ioctl32.c: make ctrl_is_pointer work for subdevs

If the device is of type VFL_TYPE_SUBDEV then vdev->ioctl_ops
is NULL so the 'if (!ops->vidioc_query_ext_ctrl)' check would crash.
Add a test for !ops to the condition.

All sub-devices that have controls will use the control framework,
so they do not have an equivalent to ops->vidioc_query_ext_ctrl.
Returning false if ops is NULL is the correct thing to do here.

Fixes: b8c601e8 ("v4l2-compat-ioctl32.c: fix ctrl_is_pointer")

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Reported-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: <stable@vger.kernel.org>      # for v4.15 and up
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>