fs/cifs: fix parsing of dfs referrals

fs/cifs: fix parsing of dfs referrals

The problem was that the first referral was parsed more than once
and so the caller tried the same referrals multiple times.

The problem was introduced partly by commit
13a7987d936648d7bbdff321e65a7298a92d158f,
where 'ref += le16_to_cpu(ref->Size);' got lost,
but that was also wrong...

Cc: <stable@vger.kernel.org>
Signed-off-by: Stefan Metzmacher <metze@samba.org>
Tested-by: Björn Jacke <bj@sernet.de>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>