cciss: fix invalid use of sizeof in cciss_find_cfgtables()

sizeof() when applied to a pointer typed expression gives the
size of the pointer, not that of the pointed data.

Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Acked-by:  <scameron@beardog.cce.hp.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>