[U-Boot] [PATCH V2] Add support for Mini2440

[Gabriel Huau]

A little review of my first patch. As you can see, I removed some
unnecessary modifications that I did in arm920t directory ... (I don't
really remember why I did it), and some modifications on drivers (nand
and i2c) that was unnecessary because I am not currently supporting
theses features.

I forget to say in my first mail that is a porting from an old version
of u-boot patched by BusError (Michel Pollet).