drm/amd/powerplay: support VCN powergate status retrieval for SW SMU

Commonly used for VCN powergate status retrieval for SW SMU.
Signed-off-by: Evan Quan <evan.quan@amd.com>
Reviewed-by: Kenneth Feng <kenneth.feng@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/powerplay/amdgpu_smu.c

@@ -338,6 +338,10 @@ int smu_common_read_sensor(struct smu_context *smu, enum amd_pp_sensors sensor,
 		*(uint32_t *)data = smu_feature_is_enabled(smu, SMU_FEATURE_DPM_VCE_BIT) ? 1 : 0;
 		*size = 4;
 		break;
+	case AMDGPU_PP_SENSOR_VCN_POWER_STATE:
+		*(uint32_t *)data = smu_feature_is_enabled(smu, SMU_FEATURE_VCN_PG_BIT) ? 1 : 0;
+		*size = 4;
+		break;
 	default:
 		ret = -EINVAL;
 		break;