memory: mtk-smi: Add return value for configure port function

In MT8188, the register to enable/disable IOMMU can only be configured
in secure world by SMC call. We should add a return value for configure
port function for preparation because SMC call may return an error result.

Signed-off-by: Chengci.Xu <chengci.xu@mediatek.com>
Reviewed-by: Yong Wu <yong.wu@mediatek.com>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20220817124608.10062-3-chengci.xu@mediatek.com