switch open-coded instances of d_make_root() to new helper

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/ecryptfs/main.c b/fs/ecryptfs/main.c
index b4a6bef..6e0e017 100644
--- a/fs/ecryptfs/main.c
+++ b/fs/ecryptfs/main.c
@@ -550,9 +550,8 @@
 	if (IS_ERR(inode))
 		goto out_free;
 
-	s->s_root = d_alloc_root(inode);
+	s->s_root = d_make_root(inode);
 	if (!s->s_root) {
-		iput(inode);
 		rc = -ENOMEM;
 		goto out_free;
 	}