mb/google/rex/var/karis: Set PCIE WLAN bluetooth companion device

To publish the Bluetooth Regulator Domain Settings under the right
ACPI device scope, the wifi generic driver requires the bluetooth
companion to be set accordingly.

BUG=b:345373187
TEST=Build and test on karis, check BRDS is shown in SSDT.

Change-Id: I28541e7a23dd486d3e0ec38ee89e1ab13595fc72
Signed-off-by: Tyler Wang <tyler.wang@quanta.corp-partner.google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/83791
Reviewed-by: Subrata Banik <subratabanik@google.com>
Reviewed-by: Jérémy Compostella <jeremy.compostella@intel.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: YH Lin <yueherngl@google.com>

src/mainboard/google/rex/variants/karis/overridetree.cb

@@ -527,6 +527,7 @@ chip soc/intel/meteorlake
 			chip drivers/wifi/generic
 				register "wake" = "GPE0_DW2_09"
 				register "add_acpi_dma_property" = "true"
+				use usb2_port10 as bluetooth_companion
 				device pci 00.0 on
 					probe WIFI_TYPE WIFI_PCIE
 				end