ENGR00155219 [MX6]Add protection for dormant mode

ENGR00155219 [MX6]Add protection for dormant mode

1. clean up ddr io code, using macro define;
2. we should consider if the wake up irq comes
during execution of low-power(ms6q_suspend.S)
code but before ARM enter wfi, in this scenario,
system will not enter STOP mode, thus, the resume
code will cause system fail, so we need to consider
if system can not enter STOP mode, should resume
immediately after wfi.

Signed-off-by: Anson Huang <b20788@freescale.com>