[media] m5mols: Enable v4l subdev device node

Set V4L2_SUBDEV_FL_HAS_DEVNODE flag for the host driver to create
the sensor device node.

Acked-by: HeungJun Kim <riverful.kim@samsung.com>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>