Introduce HSS_Tests testsuite

Change-Id: Ic2fccd9c54aea04f1a31649a0af47c974939fb2f
Related: SYS#6588
diff --git a/Makefile b/Makefile
index 1d119d1..0ed632f 100644
--- a/Makefile
+++ b/Makefile
@@ -27,6 +27,7 @@
 	hlr \
 	hnbgw \
 	hnodeb \
+	hss \
 	mgw \
 	mme \
 	msc \