[IA64-SGI] - Eliminate SN pio_phys_xxx macros. Move to assembly

Rewrite the SN pio_phys_xxx macros in assembly language. This
avoids issues with the Intel icc compiler. Function call
overhead is not an issue - the functions reference PIOs
and take 100's nsec to complete.

In addition, the functions should likely be in assembly
language anyway - they reference memory using physical
addressing mode. One function executes with psr.ic disabled.

Signed-off-by: Jack Steiner <steiner@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>