Many of IOSAPIC codes depends on the flollowing assumptions, but these
would become invalid when multiple vector domain will be supported in
the future.

  - 1:1 mapping between IRQ and vector
  - IRQ == vector

To fix those invalid assumptions, this patch changes iosapic_intr_info[]
to be indexed by irq number instead of vector.
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>