drm/virtio: Remove open-coded commit-tail function

Exactly matches the one in the helpers.

This avoids me having to roll out dma-fence critical section
annotations to this copy.
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: virtualization@lists.linux-foundation.org
Link: https://patchwork.freedesktop.org/patch/msgid/20200709123339.547390-2-daniel.vetter@ffwll.ch

drivers/gpu/drm/virtio/virtgpu_display.c

@@ -314,25 +314,6 @@ virtio_gpu_user_framebuffer_create(struct drm_device *dev,
 	return &virtio_gpu_fb->base;
 }
 
-static void vgdev_atomic_commit_tail(struct drm_atomic_state *state)
-{
-	struct drm_device *dev = state->dev;
-
-	drm_atomic_helper_commit_modeset_disables(dev, state);
-	drm_atomic_helper_commit_modeset_enables(dev, state);
-	drm_atomic_helper_commit_planes(dev, state, 0);
-
-	drm_atomic_helper_fake_vblank(state);
-	drm_atomic_helper_commit_hw_done(state);
-
-	drm_atomic_helper_wait_for_vblanks(dev, state);
-	drm_atomic_helper_cleanup_planes(dev, state);
-}
-
-static const struct drm_mode_config_helper_funcs virtio_mode_config_helpers = {
-	.atomic_commit_tail = vgdev_atomic_commit_tail,
-};
-
 static const struct drm_mode_config_funcs virtio_gpu_mode_funcs = {
 	.fb_create = virtio_gpu_user_framebuffer_create,
 	.atomic_check = drm_atomic_helper_check,
@@ -346,7 +327,6 @@ void virtio_gpu_modeset_init(struct virtio_gpu_device *vgdev)
 	drm_mode_config_init(vgdev->ddev);
 	vgdev->ddev->mode_config.quirk_addfb_prefer_host_byte_order = true;
 	vgdev->ddev->mode_config.funcs = &virtio_gpu_mode_funcs;
-	vgdev->ddev->mode_config.helper_private = &virtio_mode_config_helpers;
 
 	/* modes will be validated against the framebuffer size */
 	vgdev->ddev->mode_config.min_width = XRES_MIN;