drm/amdgpu/pm: update comment to clarify Overdrive interfaces

Vega10 and previous asics use one interface, vega20 and newer
use another.
Reviewed-by: NEvan Quan <evan.quan@amd.com>
Acked-by: NNirmoy Das <nirmoy.das@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c

@@ -696,7 +696,7 @@ static ssize_t amdgpu_set_pp_table(struct device *dev,
  * default power levels, write "r" (reset) to the file to reset them.
  *
  *
- * < For Vega20 >
+ * < For Vega20 and newer ASICs >
  *
  * Reading the file will display:
  *