nat: bsc_mgcp_clear is called from within the remove function

No need to call it twice... All endpoints should be properly
freed as part of the SCCP disconnection.
diff --git a/openbsc/src/nat/bsc_nat.c b/openbsc/src/nat/bsc_nat.c
index b3754da..a868957 100644
--- a/openbsc/src/nat/bsc_nat.c
+++ b/openbsc/src/nat/bsc_nat.c
@@ -448,10 +448,7 @@
 			break;
 		case SCCP_MSG_TYPE_RLC:
 			con = patch_sccp_src_ref_to_msc(msg, parsed, nat);
-			if (con) {
-				remove_sccp_src_ref(bsc, msg, parsed);
-				bsc_mgcp_clear(con);
-			}
+			remove_sccp_src_ref(bsc, msg, parsed);
 			break;
 		case SCCP_MSG_TYPE_UDT:
 			/* simply forward everything */