gpio: mlxbf3: fail probe if gpiochip registration fails

gpio: mlxbf3: fail probe if gpiochip registration fails

mlxbf3_gpio_probe() logs a devm_gpiochip_add_data() failure but still
returns success. That leaves the platform device bound even though the
GPIO chip was not registered.

Return the registration error so probe failure matches the missing
gpiochip state.

Fixes: cd33f216d241 ("gpio: mlxbf3: Add gpio driver support")
Signed-off-by: Pengpeng Hou <pengpeng@iscas.ac.cn>
Reviewed-by: Linus Walleij <linusw@kernel.org>
Link: https://patch.msgid.link/20260615091918.43333-1-pengpeng@iscas.ac.cn
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>