Free QualcommCameraHardware instance when closing camera

The LINK_mm_camera_destroy is being called in QualcommCameraHardware
destructor. If we do not free the QualcommCameraHardware from
camera_device_close the camera may not be deinitialized and drain
the battery when not using camera.

This is especially visible when Skype is installed - which opens the
camera during startup to probe the camera and obtains its parameters
even when the user is not using camera in skype.