udoo_spl: Initialize the eSDHC controller in SPL

Currently, imx6q udoo board fails to boot like this:

U-Boot SPL 2022.01-rc3-00061-g95ca715adad3 (Dec 18 2021 - 18:04:40 -0300)
Trying to boot from MMC1

The reason is that the eSDHC controller is not initialized in SPL.

Initialize the eSDHC controller in SPL via C code as DM is not
used in SPL.

Signed-off-by: Fabio Estevam <festevam@gmail.com>
Reviewed-by: Peter Robinson <pbrobinson@gmail.com>