libcamera: Replace iterators with structured bindings

Use structured bindings when iterating over a map in range-based for
loops. This improves readability.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Barnabás Pőcze <barnabas.pocze@ideasonboard.com>

src/libcamera/request.cpp

@@ -392,8 +392,7 @@ void Request::reuse(ReuseFlag flags)
 	_d()->reset();
 
 	if (flags & ReuseBuffers) {
-		for (auto pair : bufferMap_) {
-			FrameBuffer *buffer = pair.second;
+		for (const auto &[stream, buffer] : bufferMap_) {
 			buffer->_d()->setRequest(this);
 			_d()->pending_.insert(buffer);
 		}