staging: mt7621-dma: use devm_platform_ioremap_resource() to simplify code

Use devm_platform_ioremap_resource() to simplify the code a bit.
This is detected by coccinelle.
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20191016085833.26376-1-yuehaibing@huawei.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/mt7621-dma/mtk-hsdma.c

@@ -650,7 +650,6 @@ static int mtk_hsdma_probe(struct platform_device *pdev)
 	struct mtk_hsdma_chan *chan;
 	struct mtk_hsdam_engine *hsdma;
 	struct dma_device *dd;
-	struct resource *res;
 	int ret;
 	int irq;
 	void __iomem *base;
@@ -667,8 +666,7 @@ static int mtk_hsdma_probe(struct platform_device *pdev)
 	if (!hsdma)
 		return -EINVAL;
 
-	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	base = devm_ioremap_resource(&pdev->dev, res);
+	base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(base))
 		return PTR_ERR(base);
 	hsdma->base = base + HSDMA_BASE_OFFSET;