pinctrl: iproc-gpio: Remove redundant error printing in iproc_gpio_probe()

When devm_ioremap_resource() fails, a clear enough error message will be
printed by its subfunction __devm_ioremap_resource(). The error
information contains the device name, failure cause, and possibly resource
information.

Therefore, remove the error printing here to simplify code and reduce the
binary size.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Acked-by: Ray Jui <ray.jui@broadcom.com>
Link: https://lore.kernel.org/r/20210511085126.4287-1-thunder.leizhen@huawei.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>