meta-bletchley: phosphor-virtual-sensor: update equation of CFM sensor

update CFM sensor equation base on thermal team's request (FSC_R04)

Signed-off-by: Potin Lai <potin.lai@quantatw.com>
Change-Id: Ic10c83b79993ef1fe20a0ff2536a15fc65410e5c
diff --git a/meta-facebook/meta-bletchley/recipes-phosphor/sensors/phosphor-virtual-sensor/virtual_sensor_config.json b/meta-facebook/meta-bletchley/recipes-phosphor/sensors/phosphor-virtual-sensor/virtual_sensor_config.json
index 4fc6649..8a18092 100644
--- a/meta-facebook/meta-bletchley/recipes-phosphor/sensors/phosphor-virtual-sensor/virtual_sensor_config.json
+++ b/meta-facebook/meta-bletchley/recipes-phosphor/sensors/phosphor-virtual-sensor/virtual_sensor_config.json
@@ -36,7 +36,7 @@
         }
       ]
     },
-    "Expression": "max(0, (avg(fan0, fan1, fan2, fan3) * 0.0478) - 11.467)"
+    "Expression": "max(0, (avg(fan0, fan1, fan2, fan3) * 0.0448) - 9.5042)"
   },
   {
     "Desc": {