Add option to create metadata mount point

Test: booted metadata-encrypted device
Bug: 79781913
Change-Id: Ie922db20314c04409c98700bfb1aff3d111275f0
diff --git a/rootdir/Android.mk b/rootdir/Android.mk
index 3c9e5f3..80e068a 100644
--- a/rootdir/Android.mk
+++ b/rootdir/Android.mk
@@ -93,6 +93,9 @@
 else
   LOCAL_POST_INSTALL_CMD += ; ln -sf /system/product $(TARGET_ROOT_OUT)/product
 endif
+ifdef BOARD_USES_METADATA_PARTITION
+  LOCAL_POST_INSTALL_CMD += ; mkdir -p $(TARGET_ROOT_OUT)/metadata
+endif
 
 # For /odm partition.
 LOCAL_POST_INSTALL_CMD += ; mkdir -p $(TARGET_ROOT_OUT)/odm