mb/google/dedede/var/lantis: Configure Acoustic noise mitigation UPDs

Enable Acoustic noise mitigation for lantis and set slew rate to 1/4
which is calibrated value for the board. Other values like PreWake,
Rampup and RampDown are 0 by default.

BUG=b:183561593
BRANCH=dedede
TEST=EE verify acoustic noise test passes.

Change-Id: I5e5f24ed934910726c220678068d085b6ee2bcf6
Signed-off-by: Tony Huang <tony-huang@quanta.corp-partner.google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/51762
Reviewed-by: Karthik Ramasubramanian <kramasub@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/mainboard/google/dedede/variants/lantis/overridetree.cb b/src/mainboard/google/dedede/variants/lantis/overridetree.cb
index 368b1dd..b9d6f72 100644
--- a/src/mainboard/google/dedede/variants/lantis/overridetree.cb
+++ b/src/mainboard/google/dedede/variants/lantis/overridetree.cb
@@ -65,6 +65,12 @@
 		.tdp_pl2_override = 15,
 	}"
 
+	# Enable Acoustic noise mitigation and set slew rate to 1/4
+	# Rest of the parameters are 0 by default.
+	register "AcousticNoiseMitigation" = "1"
+	register "SlowSlewRate" = "SlewRateFastBy4"
+	register "FastPkgCRampDisable" = "1"
+
 	device domain 0 on
 		device pci 04.0 on
 			chip drivers/intel/dptf