sensor_utils: Support upper/lower fatal threshold

Add support of upper and lower fatal threshold settings. The fatal
thresholds use the `xyz.openbmc_project.Sensor.Threshold.HardShutdown`
interface as the source of threshold value.

Tested on catalina:
```
{
    "@odata.id": "/redfish/v1/Chassis/NVIDIA_HMC/Sensors/temperature_HGX_GPU_0_TEMP_0",
    "@odata.type": "#Sensor.v1_2_0.Sensor",
    "Id": "temperature_HGX_GPU_0_TEMP_0",
    "Name": "HGX GPU 0 TEMP 0",
    "Reading": 81.34375,
    "ReadingRangeMax": 127.0,
    "ReadingRangeMin": -128.0,
    "ReadingType": "Temperature",
    "ReadingUnits": "Cel",
    "Status": {
        "Health": "OK",
        "State": "Enabled"
    },
    "Thresholds": {
        "UpperCaution": {
            "Reading": 82.0
        },
        "UpperCritical": {
            "Reading": 84.0
        },
        "UpperFatal": {
            "Reading": 87.0
        }
    }
}
```
```
{
    "@odata.id": "/redfish/v1/Chassis/NVIDIA_HMC/Sensors/temperature_HGX_GPU_0_TEMP_1",
    "@odata.type": "#Sensor.v1_2_0.Sensor",
    "Id": "temperature_HGX_GPU_0_TEMP_1",
    "Name": "HGX GPU 0 TEMP 1",
    "Reading": 5.4375,
    "ReadingRangeMax": 127.0,
    "ReadingRangeMin": -128.0,
    "ReadingType": "Temperature",
    "ReadingUnits": "Cel",
    "Status": {
        "Health": "OK",
        "State": "Enabled"
    },
    "Thresholds": {
        "LowerCaution": {
            "Reading": -0.05
        },
        "LowerCritical": {
            "Reading": -4.0
        },
        "LowerFatal": {
            "Reading": -5.0
        }
    }
}
```

Change-Id: Ida54d663efdb042d21ea433d9c198c1ee4890173
Signed-off-by: Potin Lai <potin.lai@quantatw.com>
diff --git a/redfish-core/include/utils/sensor_utils.hpp b/redfish-core/include/utils/sensor_utils.hpp
index 718df34..de1998d 100644
--- a/redfish-core/include/utils/sensor_utils.hpp
+++ b/redfish-core/include/utils/sensor_utils.hpp
@@ -585,6 +585,14 @@
             properties.emplace_back(
                 "xyz.openbmc_project.Sensor.Threshold.Critical", "CriticalLow",
                 "/Thresholds/LowerCritical/Reading"_json_pointer);
+            properties.emplace_back(
+                "xyz.openbmc_project.Sensor.Threshold.HardShutdown",
+                "HardShutdownHigh",
+                "/Thresholds/UpperFatal/Reading"_json_pointer);
+            properties.emplace_back(
+                "xyz.openbmc_project.Sensor.Threshold.HardShutdown",
+                "HardShutdownLow",
+                "/Thresholds/LowerFatal/Reading"_json_pointer);
 
             /* Add additional properties specific to sensorType */
             if (sensorType == "fan_tach")