Fix a slab corruption in ieee80211softmac_auth(). The size of a buffer
was miscomputed.

see http://bugzilla.kernel.org/show_bug.cgi?id=7245Acked-by: NDaniel Drake <dsd@gentoo.org>
Signed-off-by: NLaurent Riffard <laurent.riffard@free.fr>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>