video: udlfb: don't restore fb_mmap after deferred IO cleanup

Deferred IO now preserves the fb_ops.

Cc: Bernie Thompson <bernie@plugable.com>
Cc: linux-fbdev@vger.kernel.org
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/0f12bb51a6f2a656571cd21230b7e9d5be320db4.1575022735.git.jani.nikula@intel.com

drivers/video/fbdev/udlfb.c

@@ -1037,7 +1037,6 @@ static int dlfb_ops_release(struct fb_info *info, int user)
 		fb_deferred_io_cleanup(info);
 		kfree(info->fbdefio);
 		info->fbdefio = NULL;
-		info->fbops->fb_mmap = dlfb_ops_mmap;
 	}
 
 	dev_dbg(info->dev, "release, user=%d count=%d\n", user, dlfb->fb_count);