iommu/vt-d: Detect pre enabled translation

Add code to detect whether translation is already enabled in
the IOMMU. Save this state in a flags field added to
struct intel_iommu.

Tested-by: ZhenHua Li <zhen-hual@hp.com>
Tested-by: Baoquan He <bhe@redhat.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h
index a240e61..b85b81a 100644
--- a/include/linux/intel-iommu.h
+++ b/include/linux/intel-iommu.h
@@ -320,6 +320,9 @@
 	MAX_SR_DMAR_REGS
 };
 
+#define VTD_FLAG_TRANS_PRE_ENABLED	(1 << 0)
+#define VTD_FLAG_IRQ_REMAP_PRE_ENABLED	(1 << 1)
+
 struct intel_iommu {
 	void __iomem	*reg; /* Pointer to hardware regs, virtual addr */
 	u64 		reg_phys; /* physical address of hw register set */
@@ -351,6 +354,7 @@
 #endif
 	struct device	*iommu_dev; /* IOMMU-sysfs device */
 	int		node;
+	u32		flags;      /* Software defined flags */
 };
 
 static inline void __iommu_flush_cache(