Added pre check

Dell_iDRAC_fan_controller.sh

@@ -31,6 +31,9 @@ if [ -z "$HIGH_FAN_SPEED" ] || [ -z "$CPU_TEMPERATURE_THRESHOLD_FOR_FAN_SPEED_IN
   # We define these variables to the same values than user fan control profile
   readonly HIGH_FAN_SPEED=$FAN_SPEED
   readonly CPU_TEMPERATURE_THRESHOLD_FOR_FAN_SPEED_INTERPOLATION=$CPU_TEMPERATURE_THRESHOLD
+elif [[ "$FAN_SPEED" -gt "$HIGH_FAN_SPEED" ]]; then
+  echo 'Error : $FAN_SPEED have to be less or equal to $HIGH_FAN_SPEED. Exiting.'
+  exit 1
 else
   readonly FAN_SPEED_INTERPOLATION_ENABLED=true
 fi