qcam: Add JPEG format support

When the camera provides MJPEG, use the QImage JPEG decompression code
to convert that to RGB.

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

src/qcam/viewfinder.cpp

@@ -16,9 +16,9 @@ ViewFinder::ViewFinder(QWidget *parent)
 {
 }
 
-void ViewFinder::display(const unsigned char *raw)
+void ViewFinder::display(const unsigned char *raw, size_t size)
 {
-	converter_.convert(raw, image_->bits());
+	converter_.convert(raw, size, image_);
 
 	QPixmap pixmap = QPixmap::fromImage(*image_);
 	setPixmap(pixmap);