libcamera: framebuffer: Replace vector with span in constructor

The FrameBuffer constructor takes a list of planes as an std::vector.
The caller may stores the planes in a different type of container,
resulting in the needless allocation of a temporary vector. Replace it
with a span.

Suggested-by: Daniel Rákos <daniel.rakos@rastergrid.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Barnabás Pőcze <barnabas.pocze@ideasonboard.com>

src/libcamera/pipeline/virtual/virtual.cpp

@@ -315,7 +315,8 @@ int PipelineHandlerVirtual::queueRequestDevice([[maybe_unused]] Camera *camera,
 				fmd.sequence = streamConfig.seq++;
 				fmd.timestamp = timestamp;
 
-				for (const auto [i, p] : utils::enumerate(buffer->planes()))
+				Span<const FrameBuffer::Plane> planes = buffer->planes();
+				for (const auto [i, p] : utils::enumerate(planes))
 					fmd.planes()[i].bytesused = p.length;
 
 				found = true;