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/Makefile.am b/Makefile.am
index aed6412..28c025f 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -65,6 +65,8 @@
 
 openpower_occ_control_LDFLAGS = $(generic_ld_flags)
 
+include pldm.mk
+
 org/open_power/OCC/Device/error.hpp: ${top_srcdir}/org/open_power/OCC/Device.errors.yaml
 	@mkdir -p `dirname $@`
 	$(SDBUSPLUSPLUS) -r $(top_srcdir) error exception-header org.open_power.OCC.Device > $@