[IA64] Add support for vector domain

Add fundamental support for multiple vector domain. There still exists
only one vector domain even with this patch. IRQ migration across
domain is not supported yet by this patch.

Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>