SDL: Fix pointer aliasing warning
SDL: Fix pointer aliasing warning

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