media: v4l: uapi: ccs: Add controls for analogue gain constants

Add V4L2 controls for analogue gain constants required to control
analogue gain. The values are device specific and thus need to be obtained
from the driver.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>