spi: mt7621: use devm_platform_ioremap_resource() to simplify code

Use devm_platform_ioremap_resource() to simplify the code a bit.
This is detected by coccinelle.
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20190904135918.25352-18-yuehaibing@huawei.comSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-mt7621.c

@@ -327,7 +327,6 @@ static int mt7621_spi_probe(struct platform_device *pdev)
 	struct spi_controller *master;
 	struct mt7621_spi *rs;
 	void __iomem *base;
-	struct resource *r;
 	int status = 0;
 	struct clk *clk;
 	int ret;
@@ -336,8 +335,7 @@ static int mt7621_spi_probe(struct platform_device *pdev)
 	if (!match)
 		return -EINVAL;
 
-	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	base = devm_ioremap_resource(&pdev->dev, r);
+	base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(base))
 		return PTR_ERR(base);