CVE-2023-53246 cifs: fix DFS traversal oops without CONFIG_CIFS_DFS_UPCALL

In the Linux kernel, the following vulnerability has been resolved: cifs: fix DFS traversal oops without CONFIGCIFSDFSUPCALL When compiled with CONFIGCIFSDFSUPCALL disabled, cifsdfsdautomount is NULL. cifs.ko logic for mapping CIFSFATTRDFSREFERRAL attributes to SAUTOMOUNT and corresponding dentry...