soc: rockchip: io-domain: Fix error return code in rockchip_iodomain_probe()

Fix to return a negative error code from the error handling
case instead of 0, as done elsewhere in this function.

Fixes: e943c43b ("PM: AVS: rockchip-io: Move the driver to the rockchip specific drivers")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Zhang Changzhong <zhangchangzhong@huawei.com>
Link: https://lore.kernel.org/r/1607070805-33038-1-git-send-email-zhangchangzhong@huawei.com


Signed-off-by: Heiko Stuebner <heiko@sntech.de>