Update Nvidia GPU support
Created by: TomTheBear
This PR contains different updates:
- Ability for the perfworks backend to use min,max,sum and spot values
- Don't use
fprintf
in the code but the debug/error macros provided by LIKWID -
likwid-perfctr
: Initialize the Nvidia GPU modules only if needed (user wants to measure, print or search events). See #427 (closed)