spi: ath79: simplify iomem resource mapping

Simplify the code by switching from devm_ioremap to devm_ioremap_resource.
Checking the result of platform_get_resource is not needed as
devm_ioremap_resource checks the provided resource argument for NULL.

Signed-off-by: Heiner Kallweit <[e-mail]>
Signed-off-by: Mark Brown <[e-mail]>

drivers/spi/spi-ath79.c

···
 	sp->bitbang.flags = SPI_CS_HIGH;
 
 	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	if (r == NULL) {
-		ret = -ENOENT;
-		goto err_put_master;
-	}
-
-	sp->base = devm_ioremap(&pdev->dev, r->start, resource_size(r));
-	if (!sp->base) {
-		ret = -ENXIO;
+	sp->base = devm_ioremap_resource(&pdev->dev, r);
+	if (IS_ERR(sp->base)) {
+		ret = PTR_ERR(sp->base);
 		goto err_put_master;
 	}