mfd: hi655x: Fix return value check in hi655x_pmic_probe()

In case of error, the function devm_ioremap_resource() returns ERR_PTR()
and never returns NULL. The NULL test in the return value check should
be replaced with IS_ERR(). Also remove unneeded error handling of
platform_get_resource().
Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/mfd/hi655x-pmic.c

@@ -105,12 +105,9 @@ static int hi655x_pmic_probe(struct platform_device *pdev)
 	pmic->dev = dev;
 
 	pmic->res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	if (!pmic->res)
-		return -ENOENT;
-
 	base = devm_ioremap_resource(dev, pmic->res);
-	if (!base)
-		return -ENOMEM;
+	if (IS_ERR(base))
+		return PTR_ERR(base);
 
 	pmic->regmap = devm_regmap_init_mmio_clk(dev, NULL, base,
 						 &hi655x_regmap_config);