ARM: integrator: use __iomem pointers for MMIO, part 2

Due to some interesting merges in the integrator code, not
all users of mmio pointers were converted before, this
fixes all warnings that got introduced as a consequence.

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