mmc: sdhci-esdhc-imx: add HS400_ES support for i.MX8QXP

Add an new esdhc_soc_data for i.MX8QXP, and add HS400_ES mode
support.

Signed-off-by: Haibo Chen <haibo.chen@nxp.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
[Ulf: Rebased on top of latest changes]
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>