dmaengine: hisi_dma: remove redundant irqsave and irqrestore in hardIRQ

Running in hardIRQ, disabling IRQ is redundant since hardIRQ has disabled
IRQ. This patch removes the irqsave and irqstore to save some instruction
cycles.
Signed-off-by: Barry Song <song.bao.hua@hisilicon.com>
Acked-by: Zhou Wang <wangzhou1@hisilicon.com>
Link: https://lore.kernel.org/r/20201027215252.25820-8-song.bao.hua@hisilicon.comSigned-off-by: Vinod Koul <vkoul@kernel.org>

drivers/dma/hisi_dma.c

@@ -431,9 +431,8 @@ static irqreturn_t hisi_dma_irq(int irq, void *data)
 	struct hisi_dma_dev *hdma_dev = chan->hdma_dev;
 	struct hisi_dma_desc *desc;
 	struct hisi_dma_cqe *cqe;
-	unsigned long flags;
 
-	spin_lock_irqsave(&chan->vc.lock, flags);
+	spin_lock(&chan->vc.lock);
 
 	desc = chan->desc;
 	cqe = chan->cq + chan->cq_head;
@@ -452,7 +451,7 @@ static irqreturn_t hisi_dma_irq(int irq, void *data)
 		chan->desc = NULL;
 	}
 
-	spin_unlock_irqrestore(&chan->vc.lock, flags);
+	spin_unlock(&chan->vc.lock);
 
 	return IRQ_HANDLED;
 }