libcamera: camera_sensor: Introduce CameraSensorFactory

Introduce a factory to create CameraSensor derived classes instances by
inspecting the sensor media entity name and provide a convenience macro
to register specialized sensor handlers.

Signed-off-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Stefan Klug <stefan.klug@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

src/libcamera/pipeline/vimc/vimc.cpp

@@ -532,10 +532,9 @@ int VimcCameraData::init()
 		return ret;
 
 	/* Create and open the camera sensor, debayer, scaler and video device. */
-	sensor_ = std::make_unique<CameraSensor>(media_->getEntityByName("Sensor B"));
-	ret = sensor_->init();
-	if (ret)
-		return ret;
+	sensor_ = CameraSensorFactoryBase::create(media_->getEntityByName("Sensor B"));
+	if (!sensor_)
+		return -ENODEV;
 
 	debayer_ = V4L2Subdevice::fromEntityName(media_, "Debayer B");
 	if (debayer_->open())