[CIFS] Fix endian error comparing authusers when cifsacl enabled

Fix sparse warning:
 CHECK   fs/cifs/cifsacl.c
fs/cifs/cifsacl.c:41:36: warning: incorrect type in initializer
(different base types)
fs/cifs/cifsacl.c:41:36:    expected restricted __le32
fs/cifs/cifsacl.c:41:36:    got int
fs/cifs/cifsacl.c:461:52: warning: restricted __le32 degrades to integer
fs/cifs/cifsacl.c:461:73: warning: restricted __le32 degrades to integer

The second one looks harmless but the first one (sid_authusers)
was added in commit 2fbc2f17
and only affects 2.6.38/2.6.39

CC: Stable <stable@kernel.org>
Reviewed-and-Tested-by: Shirish Pargaonkar <shirishpargaonkar@gmail.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>