lpfc: use time_after()

To be future-proof and for better readability the time comparisons
are modified to use time_after() instead of plain, error-prone math.
Signed-off-by: Manuel Schölling <manuel.schoelling@gmx.de>
Reviewed-by: James Smart <james.smart@emulex.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

drivers/scsi/lpfc/lpfc_scsi.c

@@ -380,12 +380,14 @@ lpfc_rampdown_queue_depth(struct lpfc_hba *phba)
 {
 	unsigned long flags;
 	uint32_t evt_posted;
+	unsigned long expires;
 
 	spin_lock_irqsave(&phba->hbalock, flags);
 	atomic_inc(&phba->num_rsrc_err);
 	phba->last_rsrc_error_time = jiffies;
 
-	if ((phba->last_ramp_down_time + QUEUE_RAMP_DOWN_INTERVAL) > jiffies) {
+	expires = phba->last_ramp_down_time + QUEUE_RAMP_DOWN_INTERVAL;
+	if (time_after(expires, jiffies)) {
 		spin_unlock_irqrestore(&phba->hbalock, flags);
 		return;
 	}