Since IRQF_NO_SUSPEND used for imx mailbox driver, that means this irq
can't be used for wakeup source so that can't wakeup from freeze mode.
Add pm_system_wakeup() to wakeup from freeze mode.

Signed-off-by: Robin Gong <yibin.gong@nxp.com>
Reviewed-by: Jacky Bai <ping.bai@nxp.com>
Reviewed-by: Peng Fan <peng.fan@nxp.com>