Add a V4L2 sub-device driver for the Sony IMX214 image sensor.
This is a camera sensor using the I2C bus for control and the
CSI-2 bus for data.

Tested on a DB820c alike board with Intrinsyc Open-Q 13MP camera.

[Sakari Ailus: squash exposure time max limit patch]
Signed-off-by: NRicardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Reviewed-by: NJacopo Mondi <jacopo@jmondi.org>
Signed-off-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab+samsung@kernel.org>