ia64: initialize cpu maps early

All information necessary to initialize cpu possible and present maps
are available once early_acpi_boot_init() is complete.  Reorganize
setup_arch() and acpi init functions such that,

* CPU information is printed after LAPIC entries are parsed in
  early_acpi_boot_init().

* smp_build_cpu_map() is called by setup_arch() instead of acpi
  functions.

* smp_build_cpu_map() is called once all CPU related information is
  available before memory is initialized.

This is primarily to allow find_memory() to use cpu maps but is also a
general cleanup.  Please note that with this change, the somewhat
ad-hoc early_cpu_possible_map defined and used for NUMA configurations
is probably unnecessary.  Something to clean up another day.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: linux-ia64 <linux-ia64@vger.kernel.org>