ec/h8: Store PWRS and notify CPU on AC power plug/unplug events

PWRS is is the power source gnvs.

Notifying CPU is needed to change P- and C-states on these events.

Change-Id: I0818d10474523fb14f7ba7cfbf61166b89442083
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/22931
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Rudolph <siro@das-labor.org>
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

src/ec/lenovo/h8/acpi/ac.asl

@@ -29,7 +29,10 @@ Device(AC)
 
 	Method(_PSR, 0, NotSerialized)
 	{
-		return (HPAC)
+		Store(HPAC, Local0)
+		Store(Local0, \PWRS)
+		\PNOT()
+		return (Local0)
 	}
 
 	Method(_STA, 0, NotSerialized)

src/ec/lenovo/h8/acpi/ec.asl

@@ -149,6 +149,7 @@ Device(EC)
 	Method(_Q26, 0, NotSerialized)
 	{
 		Notify (AC, 0x80)
+ 		\PNOT()
 	}
 
 	/* AC status change: not present */
@@ -156,6 +157,7 @@ Device(EC)
 	{
 		Notify (AC, 0x80)
 		Store(0x50, EVNT)
+ 		\PNOT()
 	}
 
 	Method(_Q2A, 0, NotSerialized)