gprs_ns2: drop prefix of all internal exposed function

All functions which are exposed by gprs_ns2_internal.h should not contain
the public prefix gprs_. Internal function should only contain ns2_ prefix.

Change-Id: Icecc5a918902cd10efac72bbac20780d39aab272
diff --git a/src/gb/gprs_ns2_frgre.c b/src/gb/gprs_ns2_frgre.c
index da7e53f..cc8500f 100644
--- a/src/gb/gprs_ns2_frgre.c
+++ b/src/gb/gprs_ns2_frgre.c
@@ -451,7 +451,7 @@
 			goto out;
 		case NS2_CS_CREATED:
 			frgre_alloc_vc(bind, nsvc, &saddr, dlci);
-			gprs_ns2_vc_fsm_start(nsvc);
+			ns2_vc_fsm_start(nsvc);
 			break;
 		}
 	}