GB Audio: Fix audio frame timer deserialization
GB Audio: Fix audio frame timer deserialization

mgba-emu/mgba,fr500/mgba,sergiobenrocha2/mgba,libretro/mgba,fr500/mgba,libretro/mgba,Anty-Lemon/mgba,jeremyherbert/mgba,sergiobenrocha2/mgba,jeremyherbert/mgba,Iniquitatis/mgba,sergiobenrocha2/mgba,sergiobenrocha2/mgba,mgba-emu/mgba,Anty-Lemon/mgba,jeremyherbert/mgba,fr500/mgba,jeremyherbert/mgba,Anty-Lemon/mgba,Iniquitatis/mgba,Iniquitatis/mgba,fr500/mgba,libretro/mgba,libretro/mgba,mgba-emu/mgba,mgba-emu/mgba,Iniquitatis/mgba,libretro/mgba,Anty-Lemon/mgba,sergiobenrocha2/mgba