drm/amd/pm: enable LCLK DS

Enable LCLK deep sleep and it works if we enable ASPM:
modprobe amdgpu aspm=1
Signed-off-by: Kenneth Feng <kenneth.feng@amd.com>
Reviewed-by: Evan Quan <evan.quan@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/pm/swsmu/smu11/sienna_cichlid_ppt.c

@@ -302,6 +302,9 @@ sienna_cichlid_get_allowed_feature_mask(struct smu_context *smu,
 	if (smu->dc_controlled_by_gpio)
        *(uint64_t *)feature_mask |= FEATURE_MASK(FEATURE_ACDC_BIT);
 
+	if (amdgpu_aspm == 1)
+		*(uint64_t *)feature_mask |= FEATURE_MASK(FEATURE_DS_LCLK_BIT);
+
 	return 0;
 }