f2fs: fix wrong error hanlder in f2fs_follow_link

The page_follow_link_light returns NULL and its error pointer was remained
in nd->path.
Reported-by: NDan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/namei.c

@@ -298,16 +298,14 @@ static int f2fs_unlink(struct inode *dir, struct dentry *dentry)
 
 static void *f2fs_follow_link(struct dentry *dentry, struct nameidata *nd)
 {
-	struct page *page;
+	struct page *page = page_follow_link_light(dentry, nd);
 
-	page = page_follow_link_light(dentry, nd);
-	if (IS_ERR(page))
+	if (IS_ERR_OR_NULL(page))
 		return page;
 
 	/* this is broken symlink case */
 	if (*nd_get_link(nd) == 0) {
-		kunmap(page);
-		page_cache_release(page);
+		page_put_link(dentry, nd, page);
 		return ERR_PTR(-ENOENT);
 	}
 	return page;