Add variable to define base path of yamls

Resolves openbmc/openbmc#2054

Change-Id: I183e9cbc034c9c14114301abf93318aba6fff22e
Signed-off-by: Tom Joseph <tomjoseph@in.ibm.com>
diff --git a/Makefile.am b/Makefile.am
index a78f45e..78418a1 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -6,6 +6,7 @@
 noinst_LTLIBRARIES = libmanagercommon.la libmanager.la
 
 extra_yamldir=$(YAML_PATH)/extra_interfaces.d
+base_yamldir=$(YAML_PATH)
 
 phosphor_inventory_SOURCES = app.cpp
 phosphor_inventory_LDADD = libmanager.la $(SDBUSPLUS_LIBS)
@@ -40,7 +41,7 @@
 endif
 
 generated.cpp:
-	$(AM_V_GEN)$(PYTHON) $(top_srcdir)/pimgen.py $(PIMGEN_ARGS) -d $(extra_yamldir)/.. -o $(builddir) generate-cpp
+	$(AM_V_GEN)$(PYTHON) $(top_srcdir)/pimgen.py $(PIMGEN_ARGS) -d $(base_yamldir) -o $(builddir) generate-cpp
 
 SUBDIRS = . test