[Intel-gfx] [PATCH i-g-t] tests/perf_pmu: Make the invalid-init failure place more obvious

[Chris Wilson]

Quoting Tvrtko Ursulin (2017-11-22 20:49:58)
> From: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> 
> Put the values into the assert so we know which step failed.
> 
> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
-Chris