pinctrl: npcm7xx: Add missing check for ioremap

Add check for ioremap() and return the error if it fails in order to
guarantee the success of ioremap().

Fixes: 3b588e43ee5c ("pinctrl: nuvoton: add NPCM7xx pinctrl and GPIO driver")
Signed-off-by: Jiasheng Jiang <[e-mail]>
Reviewed-by: Andy Shevchenko <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Linus Walleij <[e-mail]>

drivers/pinctrl/nuvoton/pinctrl-npcm7xx.c

···
 		}
 
 		pctrl->gpio_bank[id].base = ioremap(res.start, resource_size(&res));
+		if (!pctrl->gpio_bank[id].base)
+			return -EINVAL;
 
 		ret = bgpio_init(&pctrl->gpio_bank[id].gc, dev, 4,
 				 pctrl->gpio_bank[id].base + NPCM7XX_GP_N_DIN,