bnxt_en: Add software "missed_irqs" counter.

To keep track of the number of times the workaround code for 57500 A0
has been triggered.  This is a per NQ counter.

Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/broadcom/bnxt/bnxt.c

@@ -8909,6 +8909,7 @@ static void bnxt_chk_missed_irq(struct bnxt *bp)
 			bnxt_dbg_hwrm_ring_info_get(bp,
 				DBG_RING_INFO_GET_REQ_RING_TYPE_L2_CMPL,
 				fw_ring_id, &val[0], &val[1]);
+			cpr->missed_irqs++;
 		}
 	}
 }