media: i2c: Add ov08x40 image sensor driver

Add a V4L2 sub-device driver for Omnivision ov08X40 image sensor.
This is a camera sensor using the I2C bus for control and the
CSI-2 bus for data.

This driver supports following features:
- manual exposure and analog/digital gain control support
- vblank/hblank control support
- test pattern support
- media controller support
- runtime PM support
- support following resolutions:
  + 3856x2464 at 30FPS
  + 1928x1208 at 30FPS

Signed-off-by: Jason Chen <jason.z.chen@intel.com>
Signed-off-by: Shawn Tu <shawnx.tu@intel.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>