mb/google/volteer/var/terrador: Enable audio SMBIOS OEM string

It needs to use probe statement in overridetree.cb to enable the cache
of fw_config field implemented by cb:44782 and cb:44783.

BUG=b:161963281
TEST= dmidecode -t 11 shows correct audio fw_config.
Handle 0x0009, DMI type 11, 5 bytes
OEM Strings
	String 1: DB_USB-USB4_GEN2
	String 2: AUDIO-MAX98373_ALC5682I_I2S_UP4

Signed-off-by: Kevin Cheng <kevin.cheng@intel.com>
Change-Id: I68c19b67d945aaca3e9ebec87eb27a4b07e1a49e
Reviewed-on: https://review.coreboot.org/c/coreboot/+/45673
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Sathyanarayana Nujella <sathyanarayana.nujella@intel.com>
Reviewed-by: David Wu <david_wu@quanta.corp-partner.google.com>
Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
diff --git a/src/mainboard/google/volteer/variants/terrador/overridetree.cb b/src/mainboard/google/volteer/variants/terrador/overridetree.cb
index a42664e..95f1f8a 100644
--- a/src/mainboard/google/volteer/variants/terrador/overridetree.cb
+++ b/src/mainboard/google/volteer/variants/terrador/overridetree.cb
@@ -38,6 +38,7 @@
 				register "desc" = ""Right Speaker Amp""
 				register "name" = ""MAXR""
 				device i2c 31 on
+					probe AUDIO MAX98373_ALC5682I_I2S_UP4
 				end
 			end
 			chip drivers/i2c/max98373
@@ -47,6 +48,7 @@
 				register "desc" = ""Left Speaker Amp""
 				register "name" = ""MAXL""
 				device i2c 32 on
+					probe AUDIO MAX98373_ALC5682I_I2S_UP4
 				end
 			end
 		end # I2C #0			0xA0E8
diff --git a/src/mainboard/google/volteer/variants/todor/overridetree.cb b/src/mainboard/google/volteer/variants/todor/overridetree.cb
index a42664e..95f1f8a 100644
--- a/src/mainboard/google/volteer/variants/todor/overridetree.cb
+++ b/src/mainboard/google/volteer/variants/todor/overridetree.cb
@@ -38,6 +38,7 @@
 				register "desc" = ""Right Speaker Amp""
 				register "name" = ""MAXR""
 				device i2c 31 on
+					probe AUDIO MAX98373_ALC5682I_I2S_UP4
 				end
 			end
 			chip drivers/i2c/max98373
@@ -47,6 +48,7 @@
 				register "desc" = ""Left Speaker Amp""
 				register "name" = ""MAXL""
 				device i2c 32 on
+					probe AUDIO MAX98373_ALC5682I_I2S_UP4
 				end
 			end
 		end # I2C #0			0xA0E8