CIFS: fix mapping of SFM_SPACE and SFM_PERIOD

- trailing space maps to 0xF028
- trailing period maps to 0xF029

This fix corrects the mapping of file names which have a trailing character
that would otherwise be illegal (period or space) but is allowed by POSIX.

Signed-off-by: Bjoern Jacke <bjacke@samba.org>
CC: Stable <stable@vger.kernel.org>
Signed-off-by: Steve French <smfrench@gmail.com>