[U-Boot] MMU init code in uboot for MX31 PDK

[alfred steele]

> The MMU is not used in ARM/U-boot, at least not on the i.MX31.
I was thinking there has to be a mechnism which defines the
phystovirtual mapping table before the kernel starts running in the
virtual space and the IO peripherals to access memory space/registers.
Redboot does the same, hence i thought u-boot must be doing it
somewhere.
Please correct me if i am wrong.
-Alfred.