Add functional property for each tach sensor

Each fan's tach sensor creates a child inventory object under the fan's
inventory path containing the sensor's functional state. This child
inventory object path is the fan's path plus the tach sensor's defined
id.
i.e.)
/xyz/openbmc_project/inventory/system/chassis/motherboard/fan0/fan0_0

Change-Id: I0fe5000eadbe55d60b475ccad700b0264ed0ac75
Signed-off-by: Matthew Barth <msbarth@us.ibm.com>
diff --git a/monitor/fan.hpp b/monitor/fan.hpp
index 5a21e31..f22bd9f 100644
--- a/monitor/fan.hpp
+++ b/monitor/fan.hpp
@@ -124,6 +124,16 @@
          */
         void timerExpired(TachSensor& sensor);
 
+        /**
+         * @brief Get the name of the fan
+         *
+         * @return - The fan name
+         */
+        inline const std::string& getName() const
+        {
+            return _name;
+        }
+
     private:
 
         /**