perf/x86/amd: Add IOMMU Performance Counter resource management

perf/x86/amd: Add IOMMU Performance Counter resource management

Add functionality to check the availability of the AMD IOMMU Performance
Counters and export this functionality to other core drivers, such as in this
case, a perf AMD IOMMU PMU.  This feature is not bound to any specific AMD
family/model other than the presence of the IOMMU with P-C enabled.

The AMD IOMMU P-C support static counting only at this time.

Signed-off-by: Steven Kinney <steven.kinney@amd.com>
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1370466709-3212-2-git-send-email-suravee.suthikulpanit@amd.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>