GBA SIO: Fix regression when switching modes
GBA SIO: Fix regression when switching modes

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