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: 3b588e43 ("pinctrl: nuvoton: add NPCM7xx pinctrl and GPIO driver")
Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20230607095829.1345-1-jiasheng@iscas.ac.cn


Signed-off-by: Linus Walleij <linus.walleij@linaro.org>