scsi: lpfc: Fix oops when unloading driver while running mds diags

While mds diagnostic tests are running, if the driver is requested to be
unloaded, oops or hangs are observed.  The driver doesn't terminate the
processing of diag frames when the unload is started. As such: oops may be
seen for __lpfc_sli_release_iocbq_s4 because ring memory is referenced that
was already freed; or hangs see in lpfc_nvme_wait_for_io_drain as ios no
longer complete.

If unloading, don't process diag frames. Just clean them up.

Link: https://lore.kernel.org/r/20200803210229.23063-5-jsmart2021@gmail.com


Signed-off-by: Dick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: James Smart <jsmart2021@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>