fb: port to am335x (work-in-progress [broken])

This is my work-in-progress for the frame buffer driver.
It's full of hacks and work arounds. DO NOT USE / MERGE.

It can turn on the screen and display 1 pixel, but it
doesn't get much further than that. More work remains.

Change-Id: I0dbc345c3bf7500b181f02f06376d2d09c860585