ecryptfs: ecryptfs_dentry_info->crypt_stat is never used

... and never had anything non-NULL stored into it.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/ecryptfs/ecryptfs_kernel.h

@@ -262,10 +262,7 @@ struct ecryptfs_inode_info {
  * vfsmount too. */
 struct ecryptfs_dentry_info {
 	struct path lower_path;
-	union {
-		struct ecryptfs_crypt_stat *crypt_stat;
-		struct rcu_head rcu;
-	};
+	struct rcu_head rcu;
 };
 
 /**