zenfone6: Define Soong namespaces in the common product makefile

Change-Id: Ibea0e8fe5dbc26d8953a9735f0b38cf087805b76
diff --git a/device.mk b/device.mk
index 0aaa15c..4ff65f9 100755
--- a/device.mk
+++ b/device.mk
@@ -161,6 +161,10 @@
 PRODUCT_PACKAGES += \
     vendor.display.config@1.5
 
+# Soong namespaces
+PRODUCT_SOONG_NAMESPACES += \
+    $(LOCAL_PATH)
+
 # SP-NDK:
 PRODUCT_PACKAGES += \
     libvulkan