libcamera: request: Expose the Stream to Buffers map

Add to the Request class a method to access the map of Stream to Buffer.

With the introduction of multiple stream support, pipeline handler
should be able to access the map of streams at request queueing time.

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

include/libcamera/request.h

@@ -32,6 +32,7 @@ public:
 	Request(const Request &) = delete;
 	Request &operator=(const Request &) = delete;
 
+	const std::map<Stream *, Buffer *> &buffers() const { return bufferMap_; }
 	int setBuffers(const std::map<Stream *, Buffer *> &streamMap);
 	Buffer *findBuffer(Stream *stream) const;