asahi: only process empty tiles when clearing
What does this MR do and why?
asahi: only process empty tiles when clearing
triples fps in smo metro, lolz.
Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>Due to an influx of spam, we have had to impose restrictions on new accounts. Please see this wiki page for instructions on how to get full permissions. Sorry for the inconvenience.