GB: Fix regression with HDMAs not always properly blocking
GB: Fix regression with HDMAs not always properly blocking

Iniquitatis/mgba,Iniquitatis/mgba,libretro/mgba,mgba-emu/mgba,libretro/mgba,mgba-emu/mgba,libretro/mgba,Iniquitatis/mgba,mgba-emu/mgba,libretro/mgba,mgba-emu/mgba,libretro/mgba,Iniquitatis/mgba