libcamera: Test sensor's ability to discover ancillary devices

Use vimc lens to test sensor's ability to discover ancillary lens.

Tested with the recent kernel patch for vimc lens:
https://lore.kernel.org/linux-media/20220415023855.2568366-1-yunkec@google.com/

Signed-off-by: Yunke Cao <yunkec@google.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

src/libcamera/camera_sensor.cpp

@@ -152,7 +152,12 @@ int CameraSensor::init()
 	 */
 	if (entity_->device()->driver() == "vimc") {
 		initVimcDefaultProperties();
-		return initProperties();
+
+		ret = initProperties();
+		if (ret)
+			return ret;
+
+		return discoverAncillaryDevices();
 	}
 
 	/* Get the color filter array pattern (only for RAW sensors). */