mmc: sdhci: removed unneeded function wrappers

After commit d6463f170cf0 ("mmc: sdhci: Remove redundant runtime PM calls"),
some of original sdhci_do_xx() function wrappers becomes meaningless,
so remove them.

Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>