drm/radeon/dpm: implement UVD powergating for KB/KV

Powergate the UVD block when not in use to save power.

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 1dad80c..63b6aae 100644
--- a/drivers/gpu/drm/radeon/radeon_asic.c
+++ b/drivers/gpu/drm/radeon/radeon_asic.c
@@ -2642,6 +2642,7 @@
 		.print_power_state = &kv_dpm_print_power_state,
 		.debugfs_print_current_performance_level = &kv_dpm_debugfs_print_current_performance_level,
 		.force_performance_level = &kv_dpm_force_performance_level,
+		.powergate_uvd = &kv_dpm_powergate_uvd,
 	},
 	.pflip = {
 		.pre_page_flip = &evergreen_pre_page_flip,