mb/google/volteer: Add firmware configuration table

Add the current firmware configuration table for the volteer mainboard
and define some actions based on probe results for audio:

- When I2S options are selected disable the SoundWire GPIOs.
- When SoundWire is enabled disable the I2S GPIOs.
- When no audio is enabled disable all the GPIOs.

BUG=b:147462631
TEST=Test that GPIOs are configured as expected based on the current
value of the fw_config field in cbi.

Change-Id: I179f8b6436be83a2b37911777764bd26a0d404b7
Signed-off-by: Duncan Laurie <dlaurie@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/41215
Reviewed-by: Furquan Shaikh <furquan@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/mainboard/google/volteer/variants/baseboard/devicetree.cb b/src/mainboard/google/volteer/variants/baseboard/devicetree.cb
index 23e2f75..a55ef7d 100644
--- a/src/mainboard/google/volteer/variants/baseboard/devicetree.cb
+++ b/src/mainboard/google/volteer/variants/baseboard/devicetree.cb
@@ -1,3 +1,26 @@
+fw_config
+	field USB_DB 0 3
+		option NONE 0
+		option USB4 1
+		option USB3 2
+	end
+	field THERMAL 4 7 end
+	field AUDIO 8 10
+		option NONE 0
+		option MAX98357_ALC5682I_I2S 1
+		option MAX98373_ALC5682I_I2S 2
+		option MAX98373_ALC5682_SNDW 3
+	end
+	field TABLETMODE 11
+		option DISABLED 0
+		option ENABLED 1
+	end
+	field LTE_DB 12
+		option ABSENT 0
+		option PRESENT 1
+	end
+end
+
 chip soc/intel/tigerlake
 
 	device cpu_cluster 0 on