intel/skylake: Fix bug in VR configuration with FSP 2.0

With the move to FSP 2.0 the number of VR types supported was
reduced to 4, and the VR_RING type is no longer present.

This means all existing boards using FSP 2.0 are incorrectly
passing VR configuration into FSP as the values corresponding to
"GT Sliced" and "GT Unsliced" have changed.

Fix this by updating the skylake SOC VR handling to account for
changes in the FSP configuration and no longer provide VR_RING
type when using FSP 2.0.

BUG=b:36228330
BRANCH=none
TEST=manual: build and boot on Eve

Change-Id: I59eea9fba006a4c235d7b42d07fdc6e4f44f7351
Signed-off-by: Duncan Laurie <dlaurie@chromium.org>
Reviewed-on: https://review.coreboot.org/18818
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Furquan Shaikh <furquan@google.com>
Tested-by: build bot (Jenkins)
diff --git a/src/mainboard/intel/kblrvp/variants/rvp7/devicetree.cb b/src/mainboard/intel/kblrvp/variants/rvp7/devicetree.cb
index e79c046..3696292 100644
--- a/src/mainboard/intel/kblrvp/variants/rvp7/devicetree.cb
+++ b/src/mainboard/intel/kblrvp/variants/rvp7/devicetree.cb
@@ -65,20 +65,20 @@
 	# Determines if enable Serial IRQ. Values 0: Disabled, 1: Enabled
 	register "SerialIrqConfigSirqEnable" = "0x01"
 
-	# VR Settings Configuration for 5 Domains
-	#+----------------+-------+-------+-------------+-------------+-------+
-	#| Domain/Setting |  SA   |  IA   | Ring Sliced | GT Unsliced |  GT   |
-	#+----------------+-------+-------+-------------+-------------+-------+
-	#| Psi1Threshold  | 20A   | 20A   | 20A         | 20A         | 20A   |
-	#| Psi2Threshold  | 4A    | 5A    | 5A          | 5A          | 5A    |
-	#| Psi3Threshold  | 1A    | 1A    | 1A          | 1A          | 1A    |
-	#| Psi3Enable     | 1     | 1     | 1           | 1           | 1     |
-	#| Psi4Enable     | 1     | 1     | 1           | 1           | 1     |
-	#| ImonSlope      | 0     | 0     | 0           | 0           | 0     |
-	#| ImonOffset     | 0     | 0     | 0           | 0           | 0     |
-	#| IccMax         | 7A    | 34A   | 34A         | 35A         | 35A   |
-	#| VrVoltageLimit | 1.52V | 1.52V | 1.52V       | 1.52V       | 1.52V |
-	#+----------------+-------+-------+-------------+-------------+-------+
+	# VR Settings Configuration for 4 Domains
+	#+----------------+-------+-------+-------+-------+
+	#| Domain/Setting |  SA   |  IA   | GTUS  |  GTS  |
+	#+----------------+-------+-------+-------+-------+
+	#| Psi1Threshold  | 20A   | 20A   | 20A   | 20A   |
+	#| Psi2Threshold  | 4A    | 5A    | 5A    | 5A    |
+	#| Psi3Threshold  | 1A    | 1A    | 1A    | 1A    |
+	#| Psi3Enable     | 1     | 1     | 1     | 1     |
+	#| Psi4Enable     | 1     | 1     | 1     | 1     |
+	#| ImonSlope      | 0     | 0     | 0     | 0     |
+	#| ImonOffset     | 0     | 0     | 0     | 0     |
+	#| IccMax         | 7A    | 34A   | 35A   | 35A   |
+	#| VrVoltageLimit | 1.52V | 1.52V | 1.52V | 1.52V |
+	#+----------------+-------+-------+-------+-------+
 	register "domain_vr_config[VR_SYSTEM_AGENT]" = "{
 		.vr_config_enable = 1, \
 		.psi1threshold = 0x50, \
@@ -104,18 +104,6 @@
 		.icc_max = 0x0, \
 		.voltage_limit = 0x0 \
 	}"
-	register "domain_vr_config[VR_RING]" = "{
-		.vr_config_enable = 1, \
-		.psi1threshold = 0x50, \
-		.psi2threshold = 0x14, \
-		.psi3threshold = 0x4, \
-		.psi3enable = 1, \
-		.psi4enable = 1, \
-		.imon_slope = 0x0, \
-		.imon_offset = 0x0, \
-		.icc_max = 0x0, \
-		.voltage_limit = 0x0, \
-	}"
 
 	register "domain_vr_config[VR_GT_UNSLICED]" = "{
 		.vr_config_enable = 1, \