irqchip/imx-gpcv2: IMX GPCv2 driver for wakeup sources

IMX7D contains a new version of GPC IP block (GPCv2). It has two major
functions: power management and wakeup source management.

When the system is in WFI (wait for interrupt) mode, the GPC block
will be the first block on the platform to be activated and signaled.

In normal wait mode during cpu idle, the system can be woken up by any
enabled interrupts. In standby or suspend mode, the system can only be
wokem up by the pre-defined wakeup sources.

Based-on-patch-by: Anson Huang <b20788@freescale.com>
Signed-off-by: Shenwei Wang <shenwei.wang@freescale.com>
Cc: <linux-arm-kernel@lists.infradead.org>
Cc: <shawn.guo@linaro.org>
Cc: <jason@lakedaemon.net>
Link: http://lkml.kernel.org/r/1440443055-7291-1-git-send-email-shenwei.wang@freescale.com


Signed-off-by: Thomas Gleixner <tglx@linutronix.de>