sm6225-common: Define soong namespaces

Change-Id: I8ce9ccac3f99e172875ea644590f4b6a91bd5bc5
diff --git a/common.mk b/common.mk
index ad13f79..bd09347 100644
--- a/common.mk
+++ b/common.mk
@@ -150,6 +150,11 @@
     FrameworksResTarget \
     WifiResTarget
 
+# Soong namespaces
+PRODUCT_SOONG_NAMESPACES += \
+    $(LOCAL_PATH) \
+    hardware/xiaomi
+
 # Telephony
 PRODUCT_PACKAGES += \
     extphonelib \