The fix prevents unintended wakes from second level GPIO pin interrupts.

On some Intel Kabylake platforms, it is observed that GPIO pin interrupts
can wake the platform from suspend-to-idle, even though the IRQ is not
configured as IRQF_NO_SUSPEND or enable_irq_wake().

This can cause undesired wakes on Mobile devices such as Laptops and
Chromebook devices. For example a headset jack insertion is not a desired
wake source on Chromebook devices.

The pinctrl-intel (GPIO controller) driver implements a "Shared IRQ" model.
All GPIO pin interrupts are OR'ed and mapped to a first level IRQ14 (or
IRQ15). The driver registers an irq_chip struct and maps an irq_domain for
the GPIO pin interrupts. The IRQ14 handler demuxes and calls the second
level IRQ for the respective pin.

In the suspend entry flow, at suspend_noirq stage, the kernel disables IRQs
that are not marked for wake. The pinctrl-intel driver does not implement a
irq_disable()  callback (to take advantage of lazy disabling). The
pinctrl-intel GPIO interrupts are not disabled in hardware during suspend
entry, and thus are able to wake the SoC out of suspend-to-idle.

This patch sets the IRQCHIP_MASK_ON_SUSPEND flag for the GPIO irq_chip, to
disable the second level interrupts at suspend_noirq stage via the irq_mask
callbacks. The irq_mask callback disables the IRQs in hardware by
programming the corresponding GPIO pad registers. Only IRQs that are not
marked for wake are disabled.

Signed-off-by: Rushikesh S Kadam <rushikesh.s.kadam@intel.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-and-tested-by: Rajneesh Bhardwaj <rajneesh.bhardwaj@intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>