[media] mx2_camera: use module_platform_driver_probe()

The commit 39793c69 "[media] mx2_camera: Convert it to platform driver"
used module_platform_driver() to make code smaller,
but since the driver used platform_driver_probe is more appropriate
to use module_platform_driver_probe().

Signed-off-by: Fabio Porcedda <fabio.porcedda@gmail.com>
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>