scsi: lpfc: Fix spinlock_irq issues in lpfc_els_flush_cmd()

While reviewing the CT behavior, issues with spinlock_irq were seen. The
driver should be using spinlock_irqsave/irqrestore in the els flush
routine.

Changed to spinlock_irqsave/irqrestore.

Link: https://lore.kernel.org/r/20190922035906.10977-15-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>