RAN_Emulation: Add f_ran_register_exp()

For some reason this helper function was misssing; we only had
the version to register an imsi.

Change-Id: I9d38dbdf589ed0f5999a5aeeb31b10ca5d07de16
diff --git a/library/RAN_Emulation.ttcnpp b/library/RAN_Emulation.ttcnpp
index 9873245..295876e 100644
--- a/library/RAN_Emulation.ttcnpp
+++ b/library/RAN_Emulation.ttcnpp
@@ -1442,6 +1442,13 @@
 	}
 }
 
+/* register an expect with the BSSMAP core */
+function f_ran_register_exp(octetstring l3_enc) runs on RAN_ConnHdlr {
+	BSSAP_PROC.call(RAN_register:{l3_enc, self}) {
+		[] BSSAP_PROC.getreply(RAN_register:{?, ?}) {};
+	}
+}
+
 #ifdef RAN_EMULATION_RANAP
 /* expect a IuReleaseCommand; Confirm that; expect SCCP-level N-DISCONNET.ind */
 altstep as_iu_release_compl_disc(float t := 5.0) runs on RAN_ConnHdlr {