x64, x2apic/intr-remap: parse ioapic scope under vt-d structures

Parse the vt-d device scope structures to find the mapping between IO-APICs
and the interrupt remapping hardware units.

This will be used later for enabling Interrupt-remapping for IOAPIC devices.

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: akpm@linux-foundation.org
Cc: arjan@linux.intel.com
Cc: andi@firstfloor.org
Cc: ebiederm@xmission.com
Cc: jbarnes@virtuousgeek.org
Cc: steiner@sgi.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>

drivers/pci/dmar.c

@@ -423,6 +423,9 @@ int __init dmar_table_init(void)
 		printk(KERN_INFO PREFIX "No RMRR found\n");
 #endif
 
+#ifdef CONFIG_INTR_REMAP
+	parse_ioapics_under_ir();
+#endif
 	return 0;
 }