mb/google/guybrush/var/nipperkin: probe privacy screen device by fw_config

BUG=b:228448327
BRANCH=guybrush
TEST=emerge-guybrush coreboot chromeos-bootimage
     check ACPI device "LCD" in SSDT

Signed-off-by: Kevin Chiu <kevin.chiu.17802@gmail.com>
Change-Id: I42c5abdbe3bfab72016d56399278a7aff9e33377
Reviewed-on: https://review.coreboot.org/c/coreboot/+/63575
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Raul Rangel <rrangel@chromium.org>
Reviewed-by: Rob Barnes <robbarnes@google.com>
diff --git a/src/mainboard/google/guybrush/variants/nipperkin/overridetree.cb b/src/mainboard/google/guybrush/variants/nipperkin/overridetree.cb
index 6d6285a..85581d2 100644
--- a/src/mainboard/google/guybrush/variants/nipperkin/overridetree.cb
+++ b/src/mainboard/google/guybrush/variants/nipperkin/overridetree.cb
@@ -188,7 +188,9 @@
 					register "device[0].addr" = "0x80010400"
 					register "device[0].privacy.enabled" = "1"
 					register "device[0].privacy.gpio" = "ACPI_GPIO_OUTPUT_ACTIVE_HIGH(GPIO_18)"
-					device generic 0.0 on end
+					device generic 0.0 on
+						probe KB_MAP KB_MAP_PRIVACY
+					end
 				end
 			end
 			device ref acp on