mmc: sdhci-esdhc-imx: Remove unneeded mmc-esdhc-imx.h header

After the i.MX conversion to a DT-only platform, the mmc-esdhc-imx.h
header file is no longer used outside the driver, so move its content
to the sdhci-esdhc-imx driver and remove the header.

Signed-off-by: Fabio Estevam <festevam@gmail.com>
Link: https://lore.kernel.org/r/20210719193413.3792615-1-festevam@gmail.com


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