mb/system76/tgl: Enable Bluetooth audio offload

This has two noticeable effects:

1. Devices populate the list much quicker while scanning.
2. Devices do not disappear and reappear from the list while scanning.

Tested on system76/lemp10.

Change-Id: I598c53805785914b4e9ae7f620e724eadbe643d4
Signed-off-by: Tim Crawford <tcrawford@system76.com>
Tested-by: Daniel Sutton <daniel@system76.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/77047
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/mainboard/system76/tgl-h/devicetree.cb

@@ -68,9 +68,6 @@ chip soc/intel/tigerlake
 	# rdmsr --bitfield 31:24 --decimal 0x1A2
 	register "tcc_offset" = "8"
 
-	# Enable CNVi BT
-	register "CnviBtCore" = "true"
-
 # PM Util (soc/intel/tigerlake/pmutil.c)
 	# GPE configuration
 	register "pmc_gpe0_dw0" = "PMC_GPP_R"
@@ -101,6 +98,8 @@ chip soc/intel/tigerlake
 		# From PCH EDS(615985)
 		device ref shared_ram on end
 		device ref cnvi_wifi on
+			register "CnviBtCore" = true
+			register "CnviBtAudioOffload" = true
 			chip drivers/wifi/generic
 				register "wake" = "GPE0_PME_B0"
 				device generic 0 on end

src/mainboard/system76/tgl-u/devicetree.cb

@@ -62,9 +62,6 @@ chip soc/intel/tigerlake
 	# Thermal
 	register "tcc_offset" = "12"
 
-	# Enable CNVi BT
-	register "CnviBtCore" = "true"
-
 # Actual device tree
 	device cpu_cluster 0 on end
 
@@ -88,6 +85,8 @@ chip soc/intel/tigerlake
 		device ref gna on end
 		device ref shared_ram on end
 		device ref cnvi_wifi on
+			register "CnviBtCore" = true
+			register "CnviBtAudioOffload" = true
 			chip drivers/wifi/generic
 				register "wake" = "GPE0_PME_B0"
 				device generic 0 on end