serial: sprd: Remove unnecessary resource validation

The devm_ioremap_resource() will valid the resources, thus remove the
unnecessary resource validation in the driver.
Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Acked-by: Chunyan Zhang <chunyan.zhang@spreadtrum.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/sprd_serial.c

@@ -710,15 +710,12 @@ static int sprd_probe(struct platform_device *pdev)
 		up->uartclk = clk_get_rate(clk);
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	if (!res) {
-		dev_err(&pdev->dev, "not provide mem resource\n");
-		return -ENODEV;
-	}
-	up->mapbase = res->start;
 	up->membase = devm_ioremap_resource(&pdev->dev, res);
 	if (IS_ERR(up->membase))
 		return PTR_ERR(up->membase);
 
+	up->mapbase = res->start;
+
 	irq = platform_get_irq(pdev, 0);
 	if (irq < 0) {
 		dev_err(&pdev->dev, "not provide irq resource: %d\n", irq);