libcamera: PixelFormat: Mark all function arguments of type PixelFormat as const reference

PixelFormat was previously an alias for unsigned int but is now a
class. Make all functions taking PixelFormat do so as a const reference.

Signed-off-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

src/v4l2/v4l2_camera.cpp

@@ -88,7 +88,7 @@ void V4L2Camera::requestComplete(Request *request)
 }
 
 int V4L2Camera::configure(StreamConfiguration *streamConfigOut,
-			  const Size &size, PixelFormat pixelformat,
+			  const Size &size, const PixelFormat &pixelformat,
 			  unsigned int bufferCount)
 {
 	StreamConfiguration &streamConfig = config_->at(0);