mb/google/nissa/var/nivviks: Disable pen garage based on fw_config

BUG=b:218929856
TEST=Boot to OS on nivviks. Set fw_config in CBI and check that pen
garage is enabled/disabled as expected.

Change-Id: I2c3f5403e0f11443ad3647b8c4ae624f0b88a111
Signed-off-by: Reka Norman <rekanorman@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/64209
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Eric Lai <eric_lai@quanta.corp-partner.google.com>
diff --git a/src/mainboard/google/brya/variants/nivviks/overridetree.cb b/src/mainboard/google/brya/variants/nivviks/overridetree.cb
index 472ce4f..66c8874 100644
--- a/src/mainboard/google/brya/variants/nivviks/overridetree.cb
+++ b/src/mainboard/google/brya/variants/nivviks/overridetree.cb
@@ -12,6 +12,10 @@
 		option WFC_MIPI_OVTI5675	0
 		option WFC_ABSENT		1
 	end
+	field STYLUS 6
+		option STYLUS_PRESENT		0
+		option STYLUS_ABSENT		1
+	end
 end
 
 chip soc/intel/alderlake
@@ -75,7 +79,9 @@
 				register "key.linux_code" = "SW_PEN_INSERTED"
 				register "key.linux_input_type" = "EV_SW"
 				register "key.label" = ""pen_eject""
-				device generic 0 on end
+				device generic 0 on
+					probe STYLUS STYLUS_PRESENT
+				end
 			end
 		end
 		device ref i2c2 on