iommu: Change iommu driver to call attach_device_to_domain trace event

Change iommu driver to call attach_device_to_domain trace event. This
iommu_device class event can be enabled to trigger when devices are attached
to a domain. Trace information includes device name.

Testing:
Added trace calls to iommu_prepare_identity_map() for testing some of the
conditions that are hard to trigger. Here is the trace from the testing:

      swapper/0-1     [003] ....     1.854102: attach_device_to_domain: IOMMU: device=0000:00:02.0

Signed-off-by: Shuah Khan <shuah.kh@samsung.com>
Signed-off-by: Joerg Roedel <joro@8bytes.org>

drivers/iommu/iommu.c

@@ -685,10 +685,14 @@ EXPORT_SYMBOL_GPL(iommu_domain_free);
 
 int iommu_attach_device(struct iommu_domain *domain, struct device *dev)
 {
+	int ret;
 	if (unlikely(domain->ops->attach_dev == NULL))
 		return -ENODEV;
 
-	return domain->ops->attach_dev(domain, dev);
+	ret = domain->ops->attach_dev(domain, dev);
+	if (!ret)
+		trace_attach_device_to_domain(dev);
+	return ret;
 }
 EXPORT_SYMBOL_GPL(iommu_attach_device);