media: add V4L2_CID_UNIT_CELL_SIZE control

media: add V4L2_CID_UNIT_CELL_SIZE control

Commit 61fd036d01111679b01e4b92e6bd0cdd33809aea upstream.

This control returns the unit cell size in nanometres. The struct provides
the width and the height in separated fields to take into consideration
asymmetric pixels and/or hardware binning.
This control is required for automatic calibration of sensors/cameras.

Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Ricardo Ribalda Delgado <ribalda@kernel.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>