emulators/visualboyadvance-m: fix build on non-x86
/wrkdirs/usr/ports/emulators/visualboyadvance-m/work/visualboyadvance-m-VBA-M_Beta_2/src/gba/GBA-thumb.cpp:40:8: error: 'regparm' is not valid on this platform
static INSN_REGPARM void thumbUnknownInsn(u32 opcode)