ARM: msm: use __iomem pointers for MMIO

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

Acked-by: David Brown <davidb@codeaurora.org>
Acked-by: Stephen Boyd <sboyd@codeaurora.org>
Cc: Daniel Walker <dwalker@fifo99.com>
Cc: Bryan Huntsman <bryanh@codeaurora.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>