ARM: integrator: use __iomem pointers for MMIO

ARM is moving to stricter checks on readl/write functions,
so we need to use the correct types everywhere.

This patch has a few small conflicts with stuff in linux-next, which
we have to sort out in arm-soc.

Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Russell King <linux@arm.linux.org.uk>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>