x86, ioapic: Consolidate gsi routing info into 'struct ioapic'

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: daniel.blueman@gmail.com
Link: http://lkml.kernel.org/r/20110518233157.994002011@sbsiddha-MOBL3.sc.intel.com


Signed-off-by: Ingo Molnar <mingo@elte.hu>