i965: XML description of Haswell OA metric set

i965: XML description of Haswell OA metric set

In preparation for exposing Gen Observation Architecture performance
counters via INTEL_performance_query this adds an XML description for an
initial 'Render Metrics Basic Gen7.5' query and corresponding counters.

The intention is to auto generate code for building a query from these
counters as well as the code for normalizing the individual counters.

Note that the upstream for this XML data is currently GPU Top:

  https://github.com/rib/gputop

The files are maintained under gputop-data/ and they are themselves
derived from files in an internal 'MDAPI XML' schema. There are scripts
under gputop-scripts/ and make rules in gputop-data/Makefile.xml for
maintaining these files.

Signed-off-by: Robert Bragg <robert@sixbynine.org>
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Acked-by: Kenneth Graunke <kenneth@whitecape.org>