gta4xl: Don't explicitly include updatable_apex.mk

It is inherited by base_system.mk as of QPR2

Change-Id: I020a05b233f61ea28d03199cbc76051e6e97e1dc
diff --git a/lineage_gta4xl.mk b/lineage_gta4xl.mk
index cd97c1b..9ec59db 100644
--- a/lineage_gta4xl.mk
+++ b/lineage_gta4xl.mk
@@ -29,9 +29,6 @@
 ## Inherit some common Lineage stuff
 $(call inherit-product, vendor/lineage/config/common_full_tablet.mk)
 
-## Enable updating of APEXes
-$(call inherit-product, $(SRC_TARGET_DIR)/product/updatable_apex.mk)
-
 ## Device identifier, this must come after all inclusions
 PRODUCT_DEVICE := gta4xl
 PRODUCT_NAME := lineage_gta4xl