ARM: Add support for 64 bit register reads/writes

Add macros to read and write to 64 bit registers.

Signed-off-by: Olav Haugan <ohaugan@codeaurora.org>
Signed-off-by: Iliyan Malchev <malchev@google.com>

Conflicts:
	arch/arm/include/asm/io.h

Change-Id: Iafcab4daf0faa741a9eb137da207357f59e6cd1f