mb/google/mancomb: Add STAPM values to overridetree

Follow the FP6 IRM(#56328) to set the stapm parameter
and allow other mancomb variants boards can customize those parameters.

BUG=b:1181157669
TEST=build.

Signed-off-by: Chris Wang <chris.wang@amd.corp-partner.google.com>
Change-Id: Ib3ed76e5212a5a8b5fb4fcc3d6884ceff82377b7
Reviewed-on: https://review.coreboot.org/c/coreboot/+/52709
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Marshall Dawson <marshalldawson3rd@gmail.com>
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>

src/mainboard/google/mancomb/variants/baseboard/devicetree.cb

@@ -1,6 +1,8 @@
 # SPDX-License-Identifier: GPL-2.0-or-later
 chip soc/amd/cezanne
 
+	register "system_configuration" = "3"
+
 	# eSPI Configuration
 	register "common_config.espi_config" = "{
 		.std_io_decode_bitmap = ESPI_DECODE_IO_0x80_EN | ESPI_DECODE_IO_0X60_0X64_EN,

src/mainboard/google/mancomb/variants/mancomb/overridetree.cb

@@ -1,4 +1,12 @@
 chip soc/amd/cezanne
+
+	register "slow_ppt_limit_mW"         = "37500"
+	register "fast_ppt_limit_mW"         = "48000"
+	register "slow_ppt_time_constant_s"  = "5"
+	register "stapm_time_constant_s"     = "275"
+	register "sustained_power_limit_mW"  = "25000"
+	register "thermctl_limit_degreeC"    = "100"
+
 	device domain 0 on
 	end # domain