ec/google/chromeec: Remove notify for power button

None of the mainboards using Chrome EC set SCI mask for power
button. Thus, the EC will never generate SCI for power button
events. This change removes the Notify call for power button as part
of clean up for getting rid of the power button device in coreboot.

BUG=b:110913245

Change-Id: I86c72fd82f1a0e6d5693ebbcd58e2aea808f8817
Signed-off-by: Furquan Shaikh <furquan@google.com>
Reviewed-on: https://review.coreboot.org/27271
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

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

@@ -223,7 +223,6 @@ Device (EC0)
 	Method (_Q03, 0, NotSerialized)
 	{
 		Store ("EC: POWER BUTTON", Debug)
-		Notify (\_SB.PWRB, 0x80)
 	}
 
 	// AC Connected