libcamera: stream: Expose stride value

Expose the image stride  which may be retrieved after a video device
has been configured. It may only be retrieved at that point as the
assignment of video devices takes place at this point.

In the future video devices should be assigned at configuration
validation time and the stride value retrieved at that point.

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

include/libcamera/stream.h

@@ -42,6 +42,7 @@ struct StreamConfiguration {
 
 	PixelFormat pixelFormat;
 	Size size;
+	unsigned int stride;
 
 	unsigned int bufferCount;