Problem:
QLA4xxx firmware may assert if given more IOCBs than it can handle.

Solution:
The driver was updated to throttle the number of active IOCBs based
on the total number of IOCB buffers received from get_firmware_status
mbx_sts[2].
Signed-off-by: NKaren Higgins <karen.higgins@qlogic.com>
Signed-off-by: NVikas Chaudhary <vikas.chaudhary@qlogic.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>