media: i2c: Add driver for Sony IMX219 sensor

Adds a driver for the 8MPix Sony IMX219 CSI2 sensor.
Whilst the sensor supports 2 or 4 CSI2 data lanes, this driver
currently only supports 2 lanes.
8MPix @ 15fps, 1080P @ 30fps (cropped FOV), and 1640x1232 (2x2 binned)
@ 30fps are currently supported.

Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.org>
Tested-by: Kieran Bingham <kieran.bingham@ideasonboard.com>