drm/radeon/dpm: add debugfs support for ON/LN

This allows you to look at the current DPM state via
debugfs.

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
diff --git a/drivers/gpu/drm/radeon/radeon_asic.c b/drivers/gpu/drm/radeon/radeon_asic.c
index a2a34f8..6d4304c 100644
--- a/drivers/gpu/drm/radeon/radeon_asic.c
+++ b/drivers/gpu/drm/radeon/radeon_asic.c
@@ -1638,6 +1638,7 @@
 		.get_sclk = &sumo_dpm_get_sclk,
 		.get_mclk = &sumo_dpm_get_mclk,
 		.print_power_state = &sumo_dpm_print_power_state,
+		.debugfs_print_current_performance_level = &sumo_dpm_debugfs_print_current_performance_level,
 	},
 	.pflip = {
 		.pre_page_flip = &evergreen_pre_page_flip,