libcamera: Replace toString with operator<<() for geometry classes

Now that geometry classes implement the stream formatting operator<<(),
use it instead of the toString() function.

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

src/android/yuv/post_processor_yuv.cpp

@@ -34,8 +34,8 @@ int PostProcessorYuv::configure(const StreamConfiguration &inCfg,
 
 	if (inCfg.size < outCfg.size) {
 		LOG(YUV, Error) << "Up-scaling is not supported"
-				<< " (from " << inCfg.size.toString()
-				<< " to " << outCfg.size.toString() << ")";
+				<< " (from " << inCfg.size
+				<< " to " << outCfg.size << ")";
 		return -EINVAL;
 	}