Fix pyamdgpuinfo GPU core clock unit

Author: mathoudebine

library/sensors/sensors_python.py

@@ -339,9 +339,11 @@ def fan_percent() -> float:
     @staticmethod
     def frequency() -> float:
         if pyamdgpuinfo:
-            return pyamdgpuinfo.get_gpu(0).query_sclk()
+            return pyamdgpuinfo.get_gpu(0).query_sclk() / 1000000
         elif pyadl:
             return pyadl.ADLManager.getInstance().getDevices()[0].getCurrentEngineClock()
+        else:
+            return math.nan
 
     @staticmethod
     def is_available() -> bool: