[SCSI] qlogicpti: add missing parentheses

`+' has a higher precedence than `?' so the condition always
evaluates to true and this is preprocessed to `7*((ql) - 1)'

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>