drm/vmwgfx: Properly flush cursor updates and page-flips

With the introduction of the new command buffer mechanism,
proper care wasn't taken to flush cursor image updates and
event-less screen-target page-flips.

Fix this by introducing explicit flush points.

Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Brian Paul <brianp@vmware.com>

drivers/gpu/drm/vmwgfx/vmwgfx_kms.c

@@ -78,7 +78,7 @@ int vmw_cursor_update_image(struct vmw_private *dev_priv,
 	cmd->cursor.hotspotX = hotspotX;
 	cmd->cursor.hotspotY = hotspotY;
 
-	vmw_fifo_commit(dev_priv, cmd_size);
+	vmw_fifo_commit_flush(dev_priv, cmd_size);
 
 	return 0;
 }