The ioapic_disable_legacy() call is no longer needed for platforms do
not have legacy pic. the legacy pic abstraction has taken care it
automatically.

This patch also initialize irq-related static variables based on
information obtained from legacy_pic.
Signed-off-by: NJacob Pan <jacob.jun.pan@intel.com>
LKML-Reference: <43F901BD926A4E43B106BF17856F0755A30A7660@orsmsx508.amr.corp.intel.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>