This commit adds basic mmu support, ie:
        - DMA cache handling is not supported
        - Remapping memory region also

The current mmu setting is:
        - 4KB granularity
        - 3 level lookup (skipping L0)
        - 33 bits per VA

This is based on coreboot and u-boot mmu configuration.

Signed-off-by: Raphael Poggi <poggi.raph@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>