drm/amd/display: add missing tracepoint event in DM atomic_commit_tail

There are two events to trace the beginning and the end of
amdgpu_dm_atomic_commit_tail, but only the one ate the beginning was
placed. Place amdgpu_dm_atomic_commit_tail_finish tracepoint at the end
than.

Signed-off-by: Melissa Wen <[e-mail]>
Reviewed-by: Leo Li <[e-mail]>
Signed-off-by: Alex Deucher <[e-mail]>

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c

···
 	for (i = 0; i < crtc_disable_count; i++)
 		pm_runtime_put_autosuspend(dev->dev);
 	pm_runtime_mark_last_busy(dev->dev);
+
+	trace_amdgpu_dm_atomic_commit_tail_finish(state);
 }
 
 static int dm_force_atomic_commit(struct drm_connector *connector)