qla2xxx: Determine the number of outstanding commands based on available resources.

qla2xxx: Determine the number of outstanding commands based on available resources.

Base the number of outstanding requests the driver will keep track of on the
available resources instead of being hard-coded.

JIRA Key: V2632FC-267

Acked-by: Armen Baloyan <armen.baloyan@qlogic.com>
Acked-by: Giridhar Malavali <giridhar.malavali@qlogic.com>
Acked-by: Saurav Kashyap <saurav.kashyap@qlogic.com>
Signed-off-by: Jerry Snitselaar <jerry.snitselaar@oracle.com>