mmc: s3cmci: remove empty kerneldoc comment

Remove empty comment to fix W=1 compile warning:

    drivers/mmc/host/s3cmci.c:400: warning: Cannot understand  *
     on line 400 - I thought it was a doc line

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Link: https://lore.kernel.org/r/20200804151345.28005-1-krzk@kernel.org
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>