ipa: rkisp1: Derive rkisp1::algorithms::Agc from AgcMeanLuminance

Now that we have a AgcMeanLuminance class that centralises our AEGC
algorithm, derive the RkISP1's Agc class from it and plumb in the
necessary framework to enable it to be used. For simplicities sake
this commit switches the algorithm to use the derived class, but
does not remove the bespoke functions at this time.

Reviewed-by: Stefan Klug <stefan.klug@ideasonboard.com>
Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>
Signed-off-by: Daniel Scally <dan.scally@ideasonboard.com>
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

src/ipa/rkisp1/rkisp1.cpp

@@ -119,7 +119,7 @@ const ControlInfoMap::Map rkisp1Controls{
 } /* namespace */
 
 IPARkISP1::IPARkISP1()
-	: context_({ {}, {}, {}, { kMaxFrameContexts } })
+	: context_({ {}, {}, {}, { kMaxFrameContexts }, {} })
 {
 }
 
@@ -427,6 +427,7 @@ void IPARkISP1::updateControls(const IPACameraSensorInfo &sensorInfo,
 							      frameDurations[1],
 							      frameDurations[2]);
 
+	ctrlMap.merge(context_.ctrlMap);
 	*ipaControls = ControlInfoMap(std::move(ctrlMap), controls::controls);
 }