MPC5121: Add USB EHCI support

Signed-off-by: Francesco Rendine <francesco.rendine@valueteam.com>
Signed-off-by: Damien Dusha <d.dusha@gmail.com>
Signed-off-by: Anatolij Gustschin <agust@denx.de>

Coding style cleanup; slight file restructuring.
Signed-off-by: Wolfgang Denk <wd@denx.de>
Acked-by: Remy Bohmer <linux@bohmer.net>