mmc: Avoid open coding by using mmc_op_tuning()

Replace code with the already defined function. No functional changes.

Signed-off-by: ChanWoo Lee <cw9316.lee@samsung.com>
Reviewed-by: Adrian Hunter <adrian.hunter@intel.com>
Link: https://lore.kernel.org/r/20221124080031.14690-1-cw9316.lee@samsung.com


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