X00TD: Enforce common device & vendor tree presence

A compiled build has no chance of booting without the common device setup
and the prebuilt binaries, so fail the build if those are not present.

Change-Id: Iadd43e887d426732e549969ab8deb14194ca818d

BoardConfig.mk

@@ -5,7 +5,7 @@
 #
 
 # Inherit from sdm660-common
--include device/asus/sdm660-common/BoardConfigCommon.mk
+include device/asus/sdm660-common/BoardConfigCommon.mk
 
 DEVICE_PATH := device/asus/X00TD
 
@@ -23,4 +23,4 @@ DEVICE_MANIFEST_FILE += $(DEVICE_PATH)/manifest.xml
 TARGET_KERNEL_CONFIG := X00TD_defconfig
 
 # Inherit the proprietary files
--include vendor/asus/X00TD/BoardConfigVendor.mk
+include vendor/asus/X00TD/BoardConfigVendor.mk

device.mk

@@ -27,5 +27,5 @@ PRODUCT_COPY_FILES += \
 PRODUCT_PACKAGES += \
     X00TDWifiOverlay
 
-# Inherit proprietary files
-$(call inherit-product-if-exists, vendor/asus/X00TD/X00TD-vendor.mk)
+# Inherit the proprietary files
+$(call inherit-product, vendor/asus/X00TD/X00TD-vendor.mk)