Fix undefined count_partial if !CONFIG_SLABINFO

Small typo in the patch recently merged to avoid the unused symbol
message for count_partial(). Discussion thread with confirmation of fix at
http://marc.info/?t=120696854400001&r=1&w=2

Typo in the check if we need the count_partial function that was
introduced by 53625b4204753b904addd40ca96d9ba802e6977d

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>