mmc: fsl_esdhc: workaround for hardware 3.3v IO reliability issue

When eSDHC operates at 3.3v, damage can accumulate in an internal
level shifter at a higher than expected rate. The faster the interface
runs, the more damage accumulates. This issue now is found on LX2160A
eSDHC1 for only SD card.

The hardware workaround is recommended to use an on-board level shifter
that is 1.8v on SoC side and 3.3v on SD card side.

For boards without hardware workaround, this option could be enabled,
ensuring 1.8v IO voltage and disabling eSDHC if no card.
This option assumes no hotplug, and u-boot has to make all the way to
to linux to use 1.8v UHS-I speed mode if has card.
If you do not want the workaround for better user experience, of course
you can choose to not select it running eSDHC in unsafe mode.

Signed-off-by: Yangbo Lu <yangbo.lu@nxp.com>
Acked-by: Peng Fan <peng.fan@nxp.com>