libretro.snes9x: 29b78d -> 04692e

Upstream has broken git history [1], so the current version cannot be
fetched. The required patches have been upstreamed [2], and we hope
that upstream will be more careful with their git history.

The previous commit can still be viewed on github [3], but is not the
ancestor of any fetchable ref.

[1] https://github.com/libretro/snes9x/issues/199
[2] https://github.com/snes9xgit/snes9x/pull/588
[3] https://github.com/libretro/snes9x/commit/29b78df8c9f0f48ed4605d08a187a134b3b316d6