sm6225-common: Import `hardware/xiaomi` namespace

Change-Id: I9aca52286bcf8dd2efad42245dfff36cda02c24e
diff --git a/extract-files.py b/extract-files.py
index 93b821b..fdbbfc2 100755
--- a/extract-files.py
+++ b/extract-files.py
@@ -20,6 +20,7 @@
 
 namespace_imports = [
     'device/xiaomi/sm6225-common',
+    'hardware/xiaomi',
 ]