mb/google/brya/variants/nivviks: Enable DDR RFIM Policy for Nivviks

DDR interfaces emit electromagnetic radiation which can couple to the
antennas of various radios that are integrated in the system, and cause
radio frequency interference (RFI). The DDR Radio Frequency Interference Mitigation (DDR RFIM) feature is primarily aimed at resolving narrowband RFI from DDR4/5 and LPDDR4/5 technologies for the Wi-Fi high and ultra-high bands (~5-7 GHz). This patch sets CnviDdrRfim UPD and enables CNVI DDR RFIM feature for Nivviks variant.

Refer to Intel doc:640438 and doc:690608 for more details.

BUG=b:237238786
BRANCH=None
TEST=Build and boot Nivviks.
- Verified that Wifi DDR RFIM Feature is enabled and DDR RFI table can be modified.

Signed-off-by: Vidya Gopalakrishnan <vidya.gopalakrishnan@intel.com>
Change-Id: Iea5c6e0c404efb8231321701ea9282347e01f75d
Reviewed-on: https://review.coreboot.org/c/coreboot/+/65254
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Sumeet R Pawnikar <sumeet.r.pawnikar@intel.com>
diff --git a/src/mainboard/google/brya/variants/nivviks/overridetree.cb b/src/mainboard/google/brya/variants/nivviks/overridetree.cb
index 2188823..38b6569 100644
--- a/src/mainboard/google/brya/variants/nivviks/overridetree.cb
+++ b/src/mainboard/google/brya/variants/nivviks/overridetree.cb
@@ -175,6 +175,12 @@
 			end
 			probe WFC WFC_MIPI_OVTI5675
 		end
+		device ref cnvi_wifi on
+			chip drivers/wifi/generic
+				register "enable_cnvi_ddr_rfim" = "true"
+				device generic 0 on end
+			end
+		end
 		device ref i2c1 on
 			chip drivers/i2c/hid
 				register "generic.hid" = ""ELAN6915""