iommu: Add new member capability to struct irq_remap_ops

Add a new member 'capability' to struct irq_remap_ops for storing
information about available capabilities such as VT-d
Posted-Interrupts.

Signed-off-by: Feng Wu <feng.wu@intel.com>
Reviewed-by: Jiang Liu <jiang.liu@linux.intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Joerg Roedel <joro@8bytes.org>
Cc: iommu@lists.linux-foundation.org
Cc: dwmw2@infradead.org
Link: http://lkml.kernel.org/r/1433827237-3382-2-git-send-email-feng.wu@intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

arch/x86/include/asm/irq_remapping.h

@@ -29,6 +29,10 @@
 struct msi_msg;
 struct irq_alloc_info;
 
+enum irq_remap_cap {
+	IRQ_POSTING_CAP = 0,
+};
+
 #ifdef CONFIG_IRQ_REMAP
 
 extern void set_irq_remapping_broken(void);

drivers/iommu/irq_remapping.h

@@ -35,6 +35,9 @@ extern int no_x2apic_optout;
 extern int irq_remapping_enabled;
 
 struct irq_remap_ops {
+	/* The supported capabilities */
+	int capability;
+
 	/* Initializes hardware and makes it ready for remapping interrupts */
 	int  (*prepare)(void);