purism/librem_skl: Set TCC Activation at 95C

Set the Thermal Control Circuit (TCC) activaction value to 95C
even though FSP integration guide says to set it to 100C for SKL-U
(offset at 0), because when the TCC activates at 100C, the CPU
will have already shut itself down from overheating protection.

This was tested on Purism Librem 13 v2. A bisect showed that the
immediate shutdowns happened after commit [1] was merged which led
to this solution.

[1] ec5a947b (soc/intel/skylake: make tcc_offset take effect)

Change-Id: Idfc001c8e46ed3b07b24150c961c4b9bc9b71a62
Signed-off-by: Youness Alaoui <youness.alaoui@puri.sm>
Signed-off-by: Matt DeVillier <matt.devillier@gmail.com>
Reviewed-on: https://review.coreboot.org/25323
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>

src/mainboard/purism/librem_skl/variants/librem13v2/devicetree.cb

@@ -10,6 +10,12 @@ chip soc/intel/skylake
 	register "eist_enable" = "1"
 	register "VmxEnable" = "1"
 
+	# Set the Thermal Control Circuit (TCC) activaction value to 95C
+	# even though FSP integration guide says to set it to 100C for SKL-U
+	# (offset at 0), because when the TCC activates at 100C, the CPU
+	# will have already shut itself down from overheating protection.
+	register "tcc_offset" = "5" # TCC of 95C
+
 	# GPE configuration
 	# Note that GPE events called out in ASL code rely on this
 	# route. i.e. If this route changes then the affected GPE

src/mainboard/purism/librem_skl/variants/librem15v3/devicetree.cb

@@ -10,6 +10,12 @@ chip soc/intel/skylake
 	register "eist_enable" = "1"
 	register "VmxEnable" = "1"
 
+	# Set the Thermal Control Circuit (TCC) activaction value to 95C
+	# even though FSP integration guide says to set it to 100C for SKL-U
+	# (offset at 0), because when the TCC activates at 100C, the CPU
+	# will have already shut itself down from overheating protection.
+	register "tcc_offset" = "5" # TCC of 95C
+
 	# GPE configuration
 	# Note that GPE events called out in ASL code rely on this
 	# route. i.e. If this route changes then the affected GPE