Update z80_ctrl.c
Update z80_ctrl.c

Enforced all Z80 RAM access to volatile so the insane -03 GCC optimizations do not mess eveything up :p

Stephane-D/SGDK,andwn/SGDK,Stephane-D/SGDK,andwn/SGDK,andwn/SGDK,Stephane-D/SGDK