libcamera: Declare empty virtual destructors as defaulted

The base class of polymorphic classes is required to declare a
destructor. Several of these are empty, and can thus be declared as
defaulted.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Umang Jain <email@uajain.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

src/qcam/viewfinder.h

@@ -22,7 +22,7 @@ struct MappedBuffer {
 class ViewFinder
 {
 public:
-	virtual ~ViewFinder() {}
+	virtual ~ViewFinder() = default;
 
 	virtual const QList<libcamera::PixelFormat> &nativeFormats() const = 0;