drm/amd/pm: enable df cstate feature for SMU 13.0.0

As the feature is ready with 78.29.0 PMFW.
Signed-off-by: Evan Quan <evan.quan@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Reviewed-by: Lijo Lazar <lijo.lazar@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/pm/swsmu/smu13/smu_v13_0_0_ppt.c

@@ -223,6 +223,8 @@ smu_v13_0_0_get_allowed_feature_mask(struct smu_context *smu,
 	*(uint64_t *)feature_mask |= FEATURE_MASK(FEATURE_THROTTLERS_BIT);
 	*(uint64_t *)feature_mask |= FEATURE_MASK(FEATURE_FAN_CONTROL_BIT);
 
+	*(uint64_t *)feature_mask |= FEATURE_MASK(FEATURE_DF_CSTATE_BIT);
+
 	return 0;
 }