mb/supermicro/x11-lga1151-series: enable SLP_S0 as vendor does

This enables SLP_S0 for x11 boards.

Change-Id: I7240ed631bf72b1d3c9ea887da43772781c80b45
Signed-off-by: Michael Niewöhner <foss@mniewoehner.de>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/36141
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Michael Niewöhner
Reviewed-by: Patrick Rudolph <siro@das-labor.org>
diff --git a/src/mainboard/supermicro/x11-lga1151-series/devicetree.cb b/src/mainboard/supermicro/x11-lga1151-series/devicetree.cb
index b94bee8..1b9dc27 100644
--- a/src/mainboard/supermicro/x11-lga1151-series/devicetree.cb
+++ b/src/mainboard/supermicro/x11-lga1151-series/devicetree.cb
@@ -92,7 +92,8 @@
 	# LPC
 	register "serirq_mode" = "SERIRQ_CONTINUOUS"
 
-	# Enabling SLP_S3#, SLP_S4#, SLP_SUS and SLP_A Stretch
+	# Enabling SLP_S0, SLP_S3#, SLP_S4#, SLP_SUS and SLP_A Stretch
+	register "s0ix_enable"			= "1"
 	register "PmConfigSlpS3MinAssert"	= "SLP_S3_MIN_ASSERT_50MS"
 	register "PmConfigSlpS4MinAssert"	= "SLP_S4_MIN_ASSERT_4S"
 	register "PmConfigSlpSusMinAssert"	= "SLP_SUS_MIN_ASSERT_4S"