mmc: fsl_esdhc_imx: Use esdhc_soc_data flags to set host caps

The Linux driver automatically can detect and enable UHS, HS200, HS400
and HS400_ES automatically without extra flags being placed into the
device tree.

Right now, for U-Boot to use UHS, HS200 or HS400, the extra flags are
needed in the device tree.  Instead, go through the esdhc_soc_data
flags and enable the host caps where applicable to automatically
enable higher speeds.

Suggested-by: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Adam Ford <aford173@gmail.com>