cifs: allow sec=none mounts to work against servers that don't support extended security

In the case of sec=none, we're not sending a username or password, so
there's little benefit to mandating NTLMSSP auth. Allow it to use
unencapsulated auth in that case.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>

fs/cifs/connect.c

@@ -1061,6 +1061,7 @@ static int cifs_parse_security_flavors(char *value,
 #endif
 	case Opt_sec_none:
 		vol->nullauth = 1;
+		vol->secFlg |= CIFSSEC_MAY_NTLM;
 		break;
 	default:
 		cifs_dbg(VFS, "bad security option: %s\n", value);