mmc: via-sdmmc: remove unneeded variable 'ret'

Fix the following coccicheck warning:
./drivers/mmc/host/via-sdmmc.c:1274:5-8: Unneeded variable: "ret".
Return "0" on line 1295

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Link: https://lore.kernel.org/r/1615272478-52458-1-git-send-email-yang.lee@linux.alibaba.com


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