libcamera: pipeline: vimc: Initialize device pointers

As the device pointers are deleted in the pipelines destructor it's not
a good idea to have them uninitialized.

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

src/libcamera/pipeline/vimc.cpp

@@ -35,7 +35,7 @@ class VimcCameraData : public CameraData
 {
 public:
 	VimcCameraData(PipelineHandler *pipe)
-		: CameraData(pipe)
+		: CameraData(pipe), video_(nullptr), sensor_(nullptr)
 	{
 	}