mmc: core: remove unnecessary (void*) conversions

Pointer variables of void * type do not require type cast.

Signed-off-by: Yu Zhe <yuzhe@nfschina.com>
Link: https://lore.kernel.org/r/20230328031049.22749-1-yuzhe@nfschina.com


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