media/i2c: Add a driver for the Sony IMX708 image sensor

The imx708 is a 12MP MIPI sensor with a 16:9 aspect ratio, here using
two CSI-2 lanes. It is a "quad Bayer" sensor with all 3 modes offering
10-bit output:

12MP: 4608x2592 up to 14.35fps (full FoV)
1080p: 2304x1296 up to 56.02fps (full FoV)
720p: 1536x864 up to 120.12fps (cropped)

This imx708 sensor driver is based heavily on the imx477 driver and
has been tested on the Raspberry Pi platform using libcamera.

Signed-off-by: Nick Hollinghurst <nick.hollinghurst@raspberrypi.com>
Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>