gprs_ns2: Give NS-VC FSMs a proper name/identifier

Log output without a proper identifier is mostly useless.

Change-Id: Id9d5b0684584d03685900c6298fe70246793de14
Closes: OS#4876
diff --git a/src/gb/gprs_ns2_internal.h b/src/gb/gprs_ns2_internal.h
index c33f7f8..5dbc349 100644
--- a/src/gb/gprs_ns2_internal.h
+++ b/src/gb/gprs_ns2_internal.h
@@ -233,7 +233,8 @@
 struct gprs_ns2_vc *ns2_vc_alloc(struct gprs_ns2_vc_bind *bind,
 				 struct gprs_ns2_nse *nse,
 				 bool initiater,
-				 enum gprs_ns2_vc_mode vc_mode);
+				 enum gprs_ns2_vc_mode vc_mode,
+				 const char *id);
 
 struct msgb *gprs_ns2_msgb_alloc(void);