media: i2c: Add driver for ST VD56G3 camera sensor

Add V4L2 sub-device driver for STMicroelectronics VD56G3 camera sensor.
This is a 1.5 M pixel global shutter image sensor with an active array
size of 1124 x 1364 (portrait orientation).

The driver supports Mono (VD56G3) and Color (VD66GY) variants.

Signed-off-by: Sylvain Petinot <sylvain.petinot@foss.st.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>