vold: metadata encryption: ensure F2FS GC targets correct device.

This fixes F2FS GC failure in idle-maint.

Bug: 111953875
Change-Id: I1d10802121d5641cf9ba780fee249affd2cf6ffe
Merged-In: I1d10802121d5641cf9ba780fee249affd2cf6ffe
Test: Tested by hand
Signed-off-by: Jaegeuk Kim <jaegeuk@google.com>
diff --git a/model/PrivateVolume.h b/model/PrivateVolume.h
index 9508671..9a61f8d 100644
--- a/model/PrivateVolume.h
+++ b/model/PrivateVolume.h
@@ -41,6 +41,7 @@
     virtual ~PrivateVolume();
     const std::string& getFsType() { return mFsType; };
     const std::string& getRawDevPath() { return mRawDevPath; };
+    const std::string& getRawDmDevPath() { return mDmDevPath; };
 
 protected:
     status_t doCreate() override;