drm/virtio: get rid of drm_encoder_to_virtio_gpu_output

Not used anywhere.
Signed-off-by: Gurchetan Singh <gurchetansingh@chromium.org>
Link: http://patchwork.freedesktop.org/patch/msgid/20191219005733.18960-3-gurchetansingh@chromium.orgSigned-off-by: Gerd Hoffmann <kraxel@redhat.com>

drivers/gpu/drm/virtio/virtgpu_drv.h

@@ -137,8 +137,6 @@ struct virtio_gpu_output {
 	container_of(x, struct virtio_gpu_output, crtc)
 #define drm_connector_to_virtio_gpu_output(x) \
 	container_of(x, struct virtio_gpu_output, conn)
-#define drm_encoder_to_virtio_gpu_output(x) \
-	container_of(x, struct virtio_gpu_output, enc)
 
 struct virtio_gpu_framebuffer {
 	struct drm_framebuffer base;