qxl: drop unused variable.

this boolean isn't used anymore so drop it.
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/qxl/qxl_display.c

@@ -604,7 +604,6 @@ static int qxl_crtc_mode_set(struct drm_crtc *crtc,
 					       mode->hdisplay,
 					       mode->vdisplay);
 	}
-	qdev->mode_set = true;
 	return 0;
 }
 

drivers/gpu/drm/qxl/qxl_drv.h

@@ -270,7 +270,6 @@ struct qxl_device {
 	struct qxl_ring *cursor_ring;
 
 	struct qxl_ram_header *ram_header;
-	bool mode_set;
 
 	bool primary_created;