fs, omfs: add NULL terminator in the end up the token list

fs, omfs: add NULL terminator in the end up the token list

commit dcbff39da3d815f08750552fdd04f96b51751129 upstream.

match_token() expects a NULL terminator at the end of the token list so
that it would know where to stop.  Not having one causes it to overrun
to invalid memory.

In practice, passing a mount option that omfs didn't recognize would
sometimes panic the system.

Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Bob Copeland <me@bobcopeland.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
(cherry picked from commit a5045e0fee1a7b2cf132afb94977d4c8d781bd04)

Signed-off-by: Willy Tarreau <w@1wt.eu>