media: i2c: ov4689: CCI conversion

Convert the i2c register accesses to utilize the CCI helper library
rather than relying on driver-specific functions. Also, set analogue
gain in a single 16-bit write instead of two 8-bit writes.

[Sakari Ailus: Initialise sensor_gain as 0.]
Signed-off-by: Mikhail Rudenko <mike.rudenko@gmail.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

drivers/media/i2c/Kconfig

@@ -406,6 +406,7 @@ config VIDEO_OV2740
 config VIDEO_OV4689
 	tristate "OmniVision OV4689 sensor support"
 	depends on GPIOLIB
+	select V4L2_CCI_I2C
 	help
 	  This is a Video4Linux2 sensor-level driver for the OmniVision
 	  OV4689 camera.