[IA64] Add memory operations for xen/ia64

[IA64] Add memory operations for xen/ia64

This patch removes ugly hack upon memory operation and thus
allow inc/decrease_reservation op available for xen/ia64 now.

As a result:
  * Now we conform to common sequence where all domain pages
    are allocated together by increase_reservation before
    image builder
  * physmap table is now built at point of arch_set_info_guest
  * DOM0_GETMEMLIST can only query without allocation now

After this patch, some long-existing hacks due to mismatched
memory interface are cleaned this time. Also this is a base
step toward introducing balloon feature into xen/ia64.

Signed-off-by Kevin Tian <kevin.tian@intel.com>