media: ccs: Only add analogue gain control if the device supports it

Some devices do not implement analogue gain this way. Only add the control
when a device does have the support.

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