ARM: u300: delete all static board data

We have now transferred all the U300 peripherals to the device
tree, so we just select USE_OF, and delete all static board data,
then require that this platform shall be booted using the device
tree and nothing else.

This gets rid of the MMCI (PL180), PL022, and serial PL011
platform data entries and more.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>