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/tach_sensor.hpp b/monitor/tach_sensor.hpp
index 9b10110..59b99d2 100644
--- a/monitor/tach_sensor.hpp
+++ b/monitor/tach_sensor.hpp
@@ -167,6 +167,14 @@
          */
         void handleTachChange(sdbusplus::message::message& msg);
 
+        /**
+         * @brief Updates the Functional property in the inventory
+         *        for this tach sensor based on the value passed in.
+         *
+         * @param[in] functional - If the Functional property should
+         *                         be set to true or false.
+         */
+        void updateInventory(bool functional);
 
         /**
          * @brief the dbus object
@@ -186,6 +194,11 @@
         const std::string _name;
 
         /**
+         * @brief The inventory name of the sensor, including the full path
+         */
+        const std::string _invName;
+
+        /**
          * @brief If functional (not too slow).  The parent
          *        fan object sets this.
          */