Documentation/gpu: Fix section in the wrong scope

That section should still be inside "DRM client usage stats" rather than
as a sibling.
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221107173209.2219571-2-lucas.demarchi@intel.com

Documentation/gpu/drm-usage-stats.rst

@@ -126,7 +126,6 @@ percentage utilization of the engine, whereas drm-engine-<str> only reflects
 time active without considering what frequency the engine is operating as a
 percentage of it's maximum frequency.
 
-===============================
 Driver specific implementations
 ===============================