mmc: mediatek: fix mem leak in msdc_drv_probe

It should use mmc_free_host to free mem in error patch of
msdc_drv_probe.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Zheng Liang <zhengliang6@huawei.com>
Reviewed-by: Chaotian Jing <chaotian.jing@mediatek.com>
Link: https://lore.kernel.org/r/20201112092530.32446-1-zhengliang6@huawei.com


Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>