Add Control.FanPwm as interface.

Change-Id: I20c2c162a28b7aabf14ae17ae2f456a6b10e0e6b
Signed-off-by: Patrick Venture <venture@google.com>
Signed-off-by: Kun Yi <kunyi@google.com>
diff --git a/sensorhandler.cpp b/sensorhandler.cpp
index de3c228..036eb22 100644
--- a/sensorhandler.cpp
+++ b/sensorhandler.cpp
@@ -412,6 +412,7 @@
 const std::set<std::string> analogSensorInterfaces =
 {
     "xyz.openbmc_project.Sensor.Value",
+    "xyz.openbmc_project.Control.FanPwm",
 };
 
 bool isAnalogSensor(const std::string& interface)