Iris metrics
This merge request provides GPU metrics for Iris. The commits are structured in 3 phases:
- migrate functions from i965 into intel/perf, where they can be called by i965 and iris. Each patch should be easily reviewed as a straight move/rename refactor.
- remove functions and structs from the intel/perf interface, when they are no longer called directly by i965
- implement the gallium hooks that provide metrics for AMD_performance_monitor