Add support for Entity Association Record

Adding support for Entity Association Record (SDR type - 0x08h)
This patch includes:
1) Entity Association Record yaml file example
2) Entity Assocation Record related script and mako file changes
3) Adding Entity Association Record in get_sdr IPMI command response

From the host, tested that entity association records can be fetched

Change-Id: I9cf598e5d27d2e8c6751bbaae2176e7c976974b1
Tested: Yes
Signed-off-by: Jaghathiswari Rankappagounder Natarajan <jaghu@google.com>
diff --git a/Makefile.am b/Makefile.am
index 9bf6d4e..20af6ed 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -20,7 +20,8 @@
 libipmi20_BUILT_LIST = \
 	sensor-gen.cpp \
 	inventory-sensor-gen.cpp \
-	fru-read-gen.cpp
+	fru-read-gen.cpp \
+	entity-gen.cpp
 
 BUILT_SOURCES = \
 	ipmiwhitelist.cpp \
@@ -70,6 +71,9 @@
 fru-read-gen.cpp:
 	$(AM_V_GEN)@FRUGEN@ -o $(top_builddir) generate-cpp
 
+entity-gen.cpp:
+	$(AM_V_GEN)@ENTITYGEN@ -o $(top_builddir) generate-cpp
+
 providers_LTLIBRARIES += libipmi20.la
 libipmi20_la_SOURCES = \
 	app/channel.cpp \