drm/vkms: Use wait_for_flip_done

It's the recommended version, wait_for_vblanks is a bit a hacky
interim thing that predates all the flip_done tracking. It's
unfortunately still the default ...

Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Cc: Haneen Mohammed <hamohammed.sa@gmail.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Reviewed-by: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190719152314.7706-2-daniel.vetter@ffwll.ch

drivers/gpu/drm/vkms/vkms_drv.c

@@ -83,7 +83,7 @@ static void vkms_atomic_commit_tail(struct drm_atomic_state *old_state)
 
 	drm_atomic_helper_commit_hw_done(old_state);
 
-	drm_atomic_helper_wait_for_vblanks(dev, old_state);
+	drm_atomic_helper_wait_for_flip_done(dev, old_state);
 
 	for_each_old_crtc_in_state(old_state, crtc, old_crtc_state, i) {
 		struct vkms_crtc_state *vkms_state =