The EHL (Elkhart Lake) based platforms provide a OOB (Out of band)
service, which allows wakup device when the system is in S5 (Soft-Off
state). This OOB service can be enabled/disabled from BIOS settings. When
enabled, the ISH device gets PME wake capability. To enable PME wakeup,
driver also needs to enable ACPI GPE bit.

Once wakeup, BIOS will clear the wakeup bit to identify wakeup is
successful. So driver need to re-enable it in resume function to
keep the next wakeup capability.

Since this feature is only present on EHL, we use EHL PCI device id to
enable this feature.
Co-developed-by: Najumon Ba <najumon.ba@intel.com>
Signed-off-by: Najumon Ba <najumon.ba@intel.com>
Signed-off-by: Even Xu <even.xu@intel.com>
Signed-off-by: Zhang Lixu <lixu.zhang@intel.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>