ipa: rkisp1: Add manual color gains

Add support for manually controlling the color gains on the rkisp1 IPA.
To that end, add and plumb the AwbEnable and ColourGains controls. As
per-frame controls aren't supported yet in the rkisp1 IPA, simply apply
and perform checks on the controls immediately.

Signed-off-by: Paul Elder <paul.elder@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

src/ipa/rkisp1/ipa_context.cpp

@@ -134,6 +134,9 @@ namespace libcamera::ipa::rkisp1 {
  *
  * \var IPAFrameContext::awb.temperatureK
  * \brief Estimated color temperature
+ *
+ * \var IPAFrameContext::awb.autoEnabled
+ * \brief Whether the Auto White Balance algorithm is enabled
  */
 
 /**