intel_gpu_top: Add a sanity check discovered busy metric is per engine

Adding a cross-check with ABI config name space and not just relying on
sysfs names.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Dmitry Rogozhkin <dmitry.v.rogozhkin@intel.com>
Acked-by: Dmitry Rogozhkin <dmitry.v.rogozhkin@intel.com>