drm/radeon: add SI to r600_is_internal_thermal_sensor()

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
diff --git a/drivers/gpu/drm/radeon/r600_dpm.c b/drivers/gpu/drm/radeon/r600_dpm.c
index 28177da..e7684c6d 100644
--- a/drivers/gpu/drm/radeon/r600_dpm.c
+++ b/drivers/gpu/drm/radeon/r600_dpm.c
@@ -720,6 +720,7 @@
 	case THERMAL_TYPE_EVERGREEN:
 	case THERMAL_TYPE_SUMO:
 	case THERMAL_TYPE_NI:
+	case THERMAL_TYPE_SI:
 		return true;
 	case THERMAL_TYPE_ADT7473_WITH_INTERNAL:
 	case THERMAL_TYPE_EMC2103_WITH_INTERNAL: