mb/google/skyrim: Move SPL setting to variants

Move the sustained_power_limit_mW setting from the baseboard
to variants. This setting will be needed before STT is enabled,
but once STT is enabled, this setting should be removed.

BUG=b:265267957
BRANCH=none
TEST=Build/Boot to ChromeOS
Signed-off-by: Chris Wang <chris.wang@amd.corp-partner.google.com>

Change-Id: I7b9779600cfa8c7581732e936a714728fd618d20
Reviewed-on: https://review.coreboot.org/c/coreboot/+/73426
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Frank Wu <frank_wu@compal.corp-partner.google.com>

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

@@ -260,8 +260,6 @@ chip soc/amd/mendocino
 	register "fast_ppt_limit_mW"                     = "30000"
 	register "slow_ppt_time_constant_s"              = "5"
 	register "stapm_time_constant_s"                 = "275"
-	# Remove the sustained_power_limit_mW when STT is enabled
-	register "sustained_power_limit_mW"              = "15000"
 	register "thermctl_limit_degreeC"                = "100"
 	register "vrm_current_limit_mA"                  = "28000"
 	register "vrm_maximum_current_limit_mA"          = "50000"

src/mainboard/google/skyrim/variants/crystaldrift/overridetree.cb

@@ -21,6 +21,11 @@ fw_config
 end
 
 chip soc/amd/mendocino
+
+	# Set Package Power Parameters
+	# Remove the sustained_power_limit_mW when STT is enabled
+	register "sustained_power_limit_mW"              = "15000"
+
 	device domain 0 on
 		device ref gpp_bridge_a on  # Internal GPP Bridge 0 to Bus A
 			device ref xhci_1 on # XHCI1 controller

src/mainboard/google/skyrim/variants/markarth/overridetree.cb

@@ -2,6 +2,10 @@
 
 chip soc/amd/mendocino
 
+	# Set Package Power Parameters
+	# Remove the sustained_power_limit_mW when STT is enabled
+	register "sustained_power_limit_mW"              = "15000"
+
 	device domain 0 on
 
 		register "dxio_tx_vboost_enable" = "1"

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

@@ -27,6 +27,11 @@ fw_config
 end
 
 chip soc/amd/mendocino
+
+	# Set Package Power Parameters
+	# Remove the sustained_power_limit_mW when STT is enabled
+	register "sustained_power_limit_mW"              = "15000"
+
 	device domain 0 on
 		device ref gpp_bridge_a on  # Internal GPP Bridge 0 to Bus A
 			device ref xhci_1 on # XHCI1 controller