[IA64-SGI] move xpc.h to include/asm-ia64/sn (cleanup)

Cleanup a few items after moving xpc.h from arch/ia64/sn/kernel to
include/asm-ia64/sn.

Signed-off-by: Dean Nelson <dcn@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
4 files changed