arm: imx8ulp: release and configure XRDC at early phase

Since S400 will set the memory of SPL image to R/X. We can't write
to any data in SPL image.

1. Set the parameters save/restore only for u-boot, not for SPL. to
avoid write data.
2. Not use MU DM driver but directly call MU API to send release XRDC
to S400 at early phase.
3. Configure the SPL image memory of SRAM2 to writable (R/W/X)

Signed-off-by: Ye Li <ye.li@nxp.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>

arm: imx: basic i.MX8ULP support

Add basic i.MX8ULP support

For the MMU part, Using a simple way the calculate the MMU size to avoid
default heavy calcaulation. And align address and size in the table
settings to 2MB or 4GB as much as possible. So we can reduce the 4K page
allocations in MMU table which will spends much time in create the
page table

Signed-off-by: Ye Li <ye.li@nxp.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>