add dpm_set_power_state failure output (7xx-ni)

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
diff --git a/drivers/gpu/drm/radeon/btc_dpm.c b/drivers/gpu/drm/radeon/btc_dpm.c
index 0cbf75e..bab0185 100644
--- a/drivers/gpu/drm/radeon/btc_dpm.c
+++ b/drivers/gpu/drm/radeon/btc_dpm.c
@@ -2329,8 +2329,10 @@
 #if 0
 	/* XXX */
 	ret = rv770_unrestrict_performance_levels_after_switch(rdev);
-	if (ret)
+	if (ret) {
+		DRM_ERROR("rv770_unrestrict_performance_levels_after_switch failed\n");
 		return ret;
+	}
 #endif
 
 	return 0;