pldm: Add support for OCC state changes

When the state of the OCC changes, host sends stateSensorEvent to
indicate going active or not active which is send as a D-Bus signal
by PLDM daemon. openpower-occ-control app listens for this signal
and updates the OCC D-Bus object. The lowest entity instance number
in the PDRs corresponds to first instance of the OCC.

Tested:

1) On a simics session verified that the sensor event is handled for
OCC going active and OCCActive property is set to true.
2) A sensorEvent is generated for OCC going non active and verified
OCCActive property is set to false.
3) Powered off the host and OCCActive property is set to false.

Signed-off-by: Tom Joseph <tomjoseph@in.ibm.com>
Change-Id: I0469cc483184b66acabc5f0cea1613a7768b3393
diff --git a/occ_manager.cpp b/occ_manager.cpp
index d420eea..f59683d 100644
--- a/occ_manager.cpp
+++ b/occ_manager.cpp
@@ -111,5 +111,12 @@
 }
 #endif
 
+#ifdef PLDM
+bool Manager::updateOCCActive(instanceID instance, bool status)
+{
+    return (statusObjects[instance])->occActive(status);
+}
+#endif
+
 } // namespace occ
 } // namespace open_power