PM: wakeup: Add out-of-band system wakeup support for devices

PM: wakeup: Add out-of-band system wakeup support for devices

Some devices can wake up the system from suspend even when their power
domains are turned off. This is possible because their system-wakeup logic
resides in an always-on power domain - indicating that they support
out-of-band system wakeup.

Currently, PM domain core doesn't power off such devices if they are marked
as system wakeup sources. To better represent devices with out-of-band
wakeup capability, this patch introduces a new flag out_band_wakeup in
'struct dev_pm_info'.

Two helper APIs are added:
 - device_set_out_band_wakeup() - to mark a device as having out-of-band
   wakeup capability.
 - device_out_band_wakeup() - to query the flag.

Allow the PM core and drivers to distinguish between regular and
out-of-band wakeup sources, enable more accurate power management decision.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Reviewed-by: Dhruva Gole <d-gole@ti.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>