host-bmc: Implement Availability interface

Adding support to host Availability dbus interface. PLDM hosts this dbus
interface to provide the availability of the FRUs hosted by PLDM. The
Availability interface is defined at [1].

Tested:
   Functional test passed

[1]: https://github.com/openbmc/phosphor-dbus-interfaces/blob/master/yaml/xyz/openbmc_project/State/Decorator/Availability.interface.yaml

Change-Id: Ie5912b3683ce102a249c8b503ea9f455f0fbcabf
Signed-off-by: Archana Kakani <archana.kakani@ibm.com>
diff --git a/host-bmc/host_pdr_handler.hpp b/host-bmc/host_pdr_handler.hpp
index cabe525..352dbf4 100644
--- a/host-bmc/host_pdr_handler.hpp
+++ b/host-bmc/host_pdr_handler.hpp
@@ -264,6 +264,15 @@
      */
     void createDbusObjects(const PDRList& fruRecordSetPDRs);
 
+    /** @brief set the FRU presence based on the remote PLDM terminus off signal
+     */
+    void setPresenceFrus();
+
+    /** @brief Set the availabilty dbus Property
+     *  @param[in] path     - object path
+     */
+    void setAvailabilityState(const std::string& path);
+
     /** @brief Get FRU Record Set Identifier from FRU Record data Format
      *  @param[in] fruRecordSetPDRs - fru record set pdr
      *  @param[in] entity           - PLDM entity information