libcamera: pipeline: uvcvideo: Report new AeEnable control as available

The `AeEnable` control is handled by the `Camera` class directly, but it
still has to be added because `ControlInfoMap`s are not easily modifiable.

See 338ba00e7a ("ipa: rkisp1: agc: Report new AeEnable control as available")
for more details and a similar change in rkisp1.

Signed-off-by: Barnabás Pőcze <barnabas.pocze@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

src/libcamera/pipeline/uvcvideo/uvcvideo.cpp

@@ -596,6 +596,11 @@ int UVCCameraData::init(MediaDevice *media)
 		addControl(cid, info, &ctrls);
 	}
 
+	if (autoExposureMode_ && manualExposureMode_) {
+		/* \todo Move this to the Camera class */
+		ctrls[&controls::AeEnable] = ControlInfo(false, true, true);
+	}
+
 	controlInfo_ = ControlInfoMap(std::move(ctrls), controls::controls);
 
 	/*