ARM: integrator: move syscon remap for AP PCIv3

The Integrator/AP syscon remapping was done in the .setup()
function rather than .preinit() which is wrong - .preinit()
is called before .setup() and the former also use the syscon
base and cause a crash since it was not yet remapped.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Olof Johansson <olof@lixom.net>