mmc: sdhci-esdhc-imx: move tuning static configuration into hwinit function

Move tuning static configuration into basic hwinit function.
Tuning configuration may also be lost in low power mode, so
need restore in hwinit().

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