PEL: Add PLDM command handler

Derive a PLDMInterface class from the HostInterface class to implement
sending the 'new file available' PLDM command to notify the host of the
ID and size of PELs.

The command response is received asynchronously by watching for activity
on the MCTP file descriptor that was used for the command.  If a
response isn't received in 10 seconds, it will be considered a failure.

Both on response success and failure the class will call the registered
callback function and pass it the result.

Signed-off-by: Matt Spinler <spinler@us.ibm.com>
Change-Id: Ica00da590628cc81114a48e2831a436dc2115269
diff --git a/extensions/openpower-pels/openpower-pels.mk b/extensions/openpower-pels/openpower-pels.mk
index 220668f..e510b42 100644
--- a/extensions/openpower-pels/openpower-pels.mk
+++ b/extensions/openpower-pels/openpower-pels.mk
@@ -2,12 +2,19 @@
 	extensions/openpower-pels/entry_points.cpp \
 	extensions/openpower-pels/host_notifier.cpp \
 	extensions/openpower-pels/manager.cpp \
+	extensions/openpower-pels/pldm_interface.cpp \
 	extensions/openpower-pels/repository.cpp \
 	extensions/openpower-pels/user_data.cpp
 
 phosphor_log_manager_LDADD = \
 	libpel.la
 
+phosphor_log_manager_LDFLAGS += \
+	$(LIBPLDM_LIBS)
+
+phosphor_log_manager_CFLAGS = \
+	$(LIBPLDM_CFLAGS)
+
 noinst_LTLIBRARIES = libpel.la
 
 libpel_la_SOURCES = \