libcamera: camera: Return a pointer from generateConfiguration()

To prepare for specialising the CameraConfiguration class in pipeline
handlers, return a pointer to a camera configuration instead of a
reference from Camera::generateConfiguration(). The camera configuration
always needs to be allocated from the pipeline handler, and its
ownership is passed to the application.

For symmetry, change Camera::configure() to take a CameraConfiguration
pointer instead of a reference. This aligns with our coding practice of
passing parameters that are modified by the callee by pointer.

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

src/libcamera/include/pipeline_handler.h

@@ -60,9 +60,9 @@ public:
 	bool lock();
 	void unlock();
 
-	virtual CameraConfiguration
-	generateConfiguration(Camera *camera, const StreamRoles &roles) = 0;
-	virtual int configure(Camera *camera, CameraConfiguration &config) = 0;
+	virtual CameraConfiguration *generateConfiguration(Camera *camera,
+		const StreamRoles &roles) = 0;
+	virtual int configure(Camera *camera, CameraConfiguration *config) = 0;
 
 	virtual int allocateBuffers(Camera *camera,
 				    const std::set<Stream *> &streams) = 0;