docs: Fix SLUB docs typo

There is a minor typo in SLUB documentation.

Fix typo.

Signed-off-by: Tobin C. Harding <tobin@kernel.org>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
1 file changed