zenfone8: Include gsi_keys

Change-Id: I09df99bf537e057442dba46a06f543e722915898
diff --git a/device.mk b/device.mk
index 3df8eb5..695f2b1 100755
--- a/device.mk
+++ b/device.mk
@@ -21,6 +21,9 @@
 #
 $(call inherit-product, vendor/asus/zenfone8/zenfone8-vendor.mk)
 
+# Include GSI keys
+$(call inherit-product, $(SRC_TARGET_DIR)/product/gsi_keys.mk)
+
 # Overlays
 DEVICE_PACKAGE_OVERLAYS += \
     $(LOCAL_PATH)/overlay \