[IA64] Add PAL_VM_SUMMARY/PAL_MEM_ATTRIB to bootloader for SKI

This patch implements PAL_VM_SUMMARY (and PAL_MEM_ATTRIB for good
measure) and pretends that the simulated machine is a McKinley.

Some extra comments and clean-up by Tony Luck.

Signed-off-by: Peter Chubb <peterc@gelato.unsw.edu.au>
Signed-off-by: Tony Luck <tony.luck@intel.com>