Fix support for Ecowitt soil moisture sensors (home-assistant#151685)

Author: blotus

homeassistant/components/ecowitt/sensor.py

@@ -218,6 +218,12 @@
         native_unit_of_measurement=PERCENTAGE,
         state_class=SensorStateClass.MEASUREMENT,
     ),
+    EcoWittSensorTypes.SOIL_MOISTURE: SensorEntityDescription(
+        key="SOIL_MOISTURE",
+        device_class=SensorDeviceClass.MOISTURE,
+        native_unit_of_measurement=PERCENTAGE,
+        state_class=SensorStateClass.MEASUREMENT,
+    ),
 }