Revert part of discard "AA" commit.

I take no credit for this(it goes to Unknown and Henrik), but I haven't seen a fix pushed yet, so here it is. Unsure if it breaks Persona 3 or that Japanese game @daniel229 mentioned, but Dead or Alive and Echochrome are happy with this change.

Fixes https://github.com/hrydgard/ppsspp/issues/3455.
Reverts part of https://github.com/hrydgard/ppsspp/commit/3cd80e1c51713044d39bbb5c8a8a3a7fd9ce8e40.