ARM: io.h: Fix RTB macros to be side effect safe

Some people may call readl/writel with incrementing addresses,
i.e.

	writel(x, addr++);

but the macro will not handle this properly because addr is
used twice. Fix it.

Change-Id: I66290d8f8a6aac8c261a0d2bfd2fd7373daa6d7e
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>