mb/google/octopus/variants/meep: Disable xHCI compliance mode

Some usb devices exhibit signal loss which causes xHCI entering
compliance mode. The resolution is to disable xHCI compliance mode.

BUG=b:122671995
TEST=check "Disable Link Compliance Mode" bit of "SuperSpeed Port Link
control" register and usb operation successfully.

Change-Id: Ia2ae7e52391fadc8ed23b8b76c45d410757d22ec
Signed-off-by: Wisley Chen <wisley.chen@quantatw.com>
Reviewed-on: https://review.coreboot.org/c/30948
Reviewed-by: Karthik Ramasubramanian <kramasub@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/mainboard/google/octopus/variants/meep/overridetree.cb

@@ -112,4 +112,7 @@ chip soc/intel/apollolake
 			end
 		end	# - I2C 7
 	end
+
+	# Disable compliance mode
+	register "DisableComplianceMode" = "1"
 end