[SCSI] qla2xxx: fix sparse warning "large integer implicitly truncated to unsigned type"

Found by 0 day test project

Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Armen Baloyan <armen.baloyan@qlogic.com>
Signed-off-by: Saurav Kashyap <saurav.kashyap@qlogic.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>