media: v4l2-subdev: without controls return -ENOTTY

If the subdev did not define any controls, then return -ENOTTY if
userspace attempts to call these ioctls.

The control framework functions will return -EINVAL, not -ENOTTY if
vfh->ctrl_handler is NULL.

Several of these framework functions are also called directly from
drivers, so I don't want to change the error code there.

Found with vimc and v4l2-compliance.

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>