mainboard/ocp/monolake: Remove ACPI PNP0C0C device

Remove the empty PWRB ACPI device. The power button is controlled by
the fixed power button model in PM1x_EVT_BLK and doesn't have a
control method. The only device in mainboard.asl was PWRB, so remove
the file.

This fixes the FWTS error:
acpi_pwrb: PWR_Button field in FACP should not be zero with ACPI PNP0C0C device.

Change-Id: Idd8c3588694b913b52ca6509332603e3525117b7
Signed-off-by: Marc Jones <marcjones@sysproconsulting.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/50569
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Jay Talbott <JayTalbott@sysproconsulting.com>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>

src/mainboard/ocp/monolake/acpi/mainboard.asl

@@ -1,20 +0,0 @@
-/*
- * This file is part of the coreboot project.
- *
- * Copyright (C) 2012 Google Inc.
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License as
- * published by the Free Software Foundation; version 2 of
- * the License.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- */
-
-Device (PWRB)
-{
-	Name(_HID, EisaId("PNP0C0C"))
-}

src/mainboard/ocp/monolake/dsdt.asl

@@ -40,6 +40,4 @@ DefinitionBlock(
 
 		#include <acpi/uncore.asl>
 	}
-
-	#include "acpi/mainboard.asl"
 }