ia64: switch to NO_BOOTMEM

Since ia64 already uses memblock to register available physical memory it
is only required to move the calls to register_active_ranges() that wrap
memblock_add_node() earlier and replace bootmem memory reservations with
memblock_reserve(). Of course, all the code that find the place to put the
bootmem bitmap is removed.

Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>