mb/google/brya/var/kano: Enable Fast VMode for kano

Fast VMode nmakes the SoC throttle when the current exceeds the I_TRIP
threshold.

BUG=b:252966799
BRANCH=firmware-brya-14505.B
TEST=Verify that the feature is enabled by reading from fsp log

Change-Id: I15c3eea6ebb7f104bce0ba8cb544ecde7f488343
Signed-off-by: David Wu <david_wu@quanta.corp-partner.google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/71267
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Eric Lai <eric_lai@quanta.corp-partner.google.com>

src/mainboard/google/brya/variants/kano/overridetree.cb

@@ -22,6 +22,10 @@ fw_config
 	end
 end
 chip soc/intel/alderlake
+	register "domain_vr_config[VR_DOMAIN_IA]" = "{
+		.enable_fast_vmode = 1,
+	}"
+
 	register "sagv" = "SaGv_Enabled"
 
 	# As per Intel Advisory doc#723158, the change is required to prevent possible