pinctrl: nuvoton: ma35d1: Fix an IS_ERR() vs NULL check

The fwnode_iomap() function doesn't return error pointers, it returns
NULL.  It's the same as of_iomap() in that way.  Update the check
accordingly.

Fixes: ecc5bf8 ("pinctrl: nuvoton: Add ma35d1 pinctrl and GPIO driver")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Link: https://lore.kernel.org/r/840152f9-d3bb-410e-8164-4c5043e1983e@moroto.mountain
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

Author: Dan Carpenter

drivers/pinctrl/nuvoton/pinctrl-ma35.c

@@ -571,8 +571,8 @@ static int ma35_gpiolib_register(struct platform_device *pdev, struct ma35_pinct
 static int ma35_get_bank_data(struct ma35_pin_bank *bank)
 {
 	bank->reg_base = fwnode_iomap(bank->fwnode, 0);
-	if (IS_ERR(bank->reg_base))
-		return PTR_ERR(bank->reg_base);
+	if (!bank->reg_base)
+		return -ENOMEM;
 
 	bank->irq = fwnode_irq_get(bank->fwnode, 0);