[media] smiapp: Set device for pixel array and binner

The dev field of the v4l2_subdev was left NULL for the pixel array and
binner sub-devices. Fix this.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>