scsi: lpfc: fix lpfc_nvmet_mrq to be bound by hdw queue count

Currently, lpfc_nvmet_mrq is always scaled back to the min(lpfc_nvmet_mrq,
lpfc_irq_chann). There's no reason to reduce it to the number of interrupt
vectors.  Rather, it should be scaled down based on the number of hardware
queues for the system (if lower than max of 16).

Change scaling to use hardware queue count rather than interrupt vector
count.

Link: https://lore.kernel.org/r/20191018211832.7917-2-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>