regulator: stm32-vrefbuf: 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/20191009150138.11640-1-yuehaibing@huawei.comSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/regulator/stm32-vrefbuf.c

@@ -181,7 +181,6 @@ static const struct regulator_desc stm32_vrefbuf_regu = {
 
 static int stm32_vrefbuf_probe(struct platform_device *pdev)
 {
-	struct resource *res;
 	struct stm32_vrefbuf *priv;
 	struct regulator_config config = { };
 	struct regulator_dev *rdev;
@@ -192,8 +191,7 @@ static int stm32_vrefbuf_probe(struct platform_device *pdev)
 		return -ENOMEM;
 	priv->dev = &pdev->dev;
 
-	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	priv->base = devm_ioremap_resource(&pdev->dev, res);
+	priv->base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(priv->base))
 		return PTR_ERR(priv->base);