iommu/vt-d: Add trace events for device dma map/unmap

This adds trace support for the Intel IOMMU driver. It
also declares some events which could be used to trace
the events when an IOVA is being mapped or unmapped in
a domain.

Cc: Ashok Raj <ashok.raj@intel.com>
Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Joerg Roedel <jroedel@suse.de>