ec/google/chromeec: Call \PNOT () on initializing AC power state

This change calls \PNOT () method when AC power state is initialized
to allow platform code to take appropriate action.

BUG=b:157752693

Signed-off-by: Furquan Shaikh <furquan@google.com>
Change-Id: I089e9096f78728ddc5df2d8cb8f22f65b30b02dc
Reviewed-on: https://review.coreboot.org/c/coreboot/+/42315
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-by: Raul Rangel <rrangel@chromium.org>

src/ec/google/chromeec/acpi/ec.asl

@@ -147,6 +147,12 @@ Device (EC0)
 	{
 		// Initialize AC power state
 		Store (ACEX, \PWRS)
+		/*
+		 * Inform platform code about the current AC power state.
+		 * This allows the platform to take any action based on the initialized state.
+		 * PWRS isn't valid before this point.
+		 */
+		\PNOT ()
 
 		// Initialize LID switch state
 		Store (LIDS, \LIDS)