mmc: rtsx_usb_sdmmc: simplify the return expression of sd_change_phase()

Simplify the return expression.

Signed-off-by: Qinglang Miao <miaoqinglang@huawei.com>
Link: https://lore.kernel.org/r/20200921131042.92340-1-miaoqinglang@huawei.com


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