drm/xe: Add forcewake_all debugfs file.

We currently have no way to forcewake the gpu from the user space. So, IGT gets kind of limited.

For instance, for the latency tests we need to directly access the timestamp registers from IGT. If the gpu is in RC6 for instance, these registers will return 0 and mess with the tests. So, we need a reliable way from the IGT to enforce the GT is awake.

This mechanism is similar to the i915_forcewake_user. But here calling forcewake_all because we are really going through all the GTs and using the forcewake_all domain.

Signed-off-by: Rodrigo Vivi rodrigo.vivi@intel.com