Fix warnings in CircleBuffer
Fix warnings in CircleBuffer

Iniquitatis/mgba,sergiobenrocha2/mgba,fr500/mgba,cassos/mgba,mgba-emu/mgba,cassos/mgba,Anty-Lemon/mgba,askotx/mgba,mgba-emu/mgba,matthewbauer/mgba,sergiobenrocha2/mgba,Touched/mgba,sergiobenrocha2/mgba,zerofalcon/mgba,iracigt/mgba,Iniquitatis/mgba,AdmiralCurtiss/mgba,mgba-emu/mgba,libretro/mgba,cassos/mgba,Anty-Lemon/mgba,Touched/mgba,libretro/mgba,AdmiralCurtiss/mgba,jeremyherbert/mgba,MerryMage/mgba,AdmiralCurtiss/mgba,jeremyherbert/mgba,libretro/mgba,mgba-emu/mgba,Anty-Lemon/mgba,sergiobenrocha2/mgba,Iniquitatis/mgba,Iniquitatis/mgba,Touched/mgba,matthewbauer/mgba,askotx/mgba,askotx/mgba,bentley/mgba,fr500/mgba,iracigt/mgba,nattthebear/mgba,libretro/mgba,zerofalcon/mgba,bentley/mgba,jeremyherbert/mgba,iracigt/mgba,askotx/mgba,libretro/mgba,zerofalcon/mgba,fr500/mgba,iracigt/mgba,MerryMage/mgba,fr500/mgba,sergiobenrocha2/mgba,jeremyherbert/mgba,MerryMage/mgba,nattthebear/mgba,Anty-Lemon/mgba