spi: sifive: 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/20190904135918.25352-27-yuehaibing@huawei.comSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-sifive.c

@@ -292,7 +292,6 @@ sifive_spi_transfer_one(struct spi_master *master, struct spi_device *device,
 static int sifive_spi_probe(struct platform_device *pdev)
 {
 	struct sifive_spi *spi;
-	struct resource *res;
 	int ret, irq, num_cs;
 	u32 cs_bits, max_bits_per_word;
 	struct spi_master *master;
@@ -307,8 +306,7 @@ static int sifive_spi_probe(struct platform_device *pdev)
 	init_completion(&spi->done);
 	platform_set_drvdata(pdev, master);
 
-	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	spi->regs = devm_ioremap_resource(&pdev->dev, res);
+	spi->regs = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(spi->regs)) {
 		ret = PTR_ERR(spi->regs);
 		goto put_master;