MLK-18004: ARM: imx: pm-imx7ulp: fix resume failure in freeze mode

MLK-18004: ARM: imx: pm-imx7ulp: fix resume failure in freeze mode

This patch fix resume failure in freeze suspend mode on i.mx7ULP
("echo freeze > /sys/power/state") while pressing onoff key or
enabling rtc alarm wakeup. In freeze mode, kernel can only be woken
up by drivers which register wakup source such as 'device_init_wakeup'
or 'irq_set_irq_wake', otherwise, kernel will wait for irq handler
freeze_wake(). Unfortunately, our NMI interrupt which used to wakeup
A7 by M4 is not a common device and request irq as 'IRQF_NO_SUSPEND'
which means feeze_wake() never get chance to run while wakeup by any
event from M4 such as RTC, ONOFF. In this case, use pm_system_wakeup()
instead in NMI interrupt handle to trigger freeze_wake() directly.

Signed-off-by: Robin Gong <yibin.gong@nxp.com>
Reviewed-by: Anson Huang <Anson.Huang@nxp.com>