tests/a5: Add a5 regression testing

Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
diff --git a/configure.ac b/configure.ac
index 69b8ff7..450ccd3 100644
--- a/configure.ac
+++ b/configure.ac
@@ -164,6 +164,7 @@
 	tests/ussd/Makefile
 	tests/smscb/Makefile
 	tests/bits/Makefile
+	tests/a5/Makefile
 	utils/Makefile
 	Doxyfile.core
 	Doxyfile.gsm