watchdog: ar7_wdt: Make use of the helper function devm_platform_ioremap_resource_byname()

Use the devm_platform_ioremap_resource_byname() helper instead of
calling platform_get_resource_byname() and devm_ioremap_resource()
separately
Signed-off-by: Cai Huoqing <caihuoqing@baidu.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20210907074223.2706-1-caihuoqing@baidu.comSigned-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

drivers/watchdog/ar7_wdt.c

@@ -63,8 +63,6 @@ static DEFINE_SPINLOCK(wdt_lock);
 /* XXX currently fixed, allows max margin ~68.72 secs */
 #define prescale_value 0xffff
 
-/* Resource of the WDT registers */
-static struct resource *ar7_regs_wdt;
 /* Pointer to the remapped WDT IO space */
 static struct ar7_wdt *ar7_wdt;
 
@@ -265,9 +263,7 @@ static int ar7_wdt_probe(struct platform_device *pdev)
 {
 	int rc;
 
-	ar7_regs_wdt =
-		platform_get_resource_byname(pdev, IORESOURCE_MEM, "regs");
-	ar7_wdt = devm_ioremap_resource(&pdev->dev, ar7_regs_wdt);
+	ar7_wdt = devm_platform_ioremap_resource_byname(pdev, "regs");
 	if (IS_ERR(ar7_wdt))
 		return PTR_ERR(ar7_wdt);