Register V4L2 subdevice implemented by the driver to the V4L2
asynchronous subdevice framework.

[Sakari Ailus: Remove extra call to v4l2_i2c_subdev_set_name]
Signed-off-by: Janusz Krzysztofik <jmkrzyszt@gmail.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>