Use negative numbers for non-spec osmo-specific timers

(values -1 and -2 cannot be used because they are already taken).

Related: OS#3928
Change-Id: Ibcdb05ff5bb8efe6cb95cf94e2c8e418dc8deced
diff --git a/src/gprs_bssgp_pcu.c b/src/gprs_bssgp_pcu.c
index 4170a66..06e1814 100644
--- a/src/gprs_bssgp_pcu.c
+++ b/src/gprs_bssgp_pcu.c
@@ -975,7 +975,7 @@
 	if (!the_pcu->bssgp.bvc_sig_reset) {
 		LOGP(DBSSGP, LOGL_INFO, "Sending reset on BVCI 0\n");
 		bssgp_tx_bvc_reset(the_pcu->bssgp.bctx, 0, BSSGP_CAUSE_OML_INTERV);
-		secs = osmo_tdef_get(the_pcu->T_defs, 2, OSMO_TDEF_S, -1);
+		secs = osmo_tdef_get(the_pcu->T_defs, -102, OSMO_TDEF_S, -1);
 		osmo_timer_schedule(&the_pcu->bssgp.bvc_timer, secs, 0);
 		return;
 	}
@@ -984,7 +984,7 @@
 		LOGP(DBSSGP, LOGL_INFO, "Sending reset on BVCI %d\n",
 			the_pcu->bssgp.bctx->bvci);
 		bssgp_tx_bvc_reset(the_pcu->bssgp.bctx, the_pcu->bssgp.bctx->bvci, BSSGP_CAUSE_OML_INTERV);
-		secs = osmo_tdef_get(the_pcu->T_defs, 2, OSMO_TDEF_S, -1);
+		secs = osmo_tdef_get(the_pcu->T_defs, -102, OSMO_TDEF_S, -1);
 		osmo_timer_schedule(&the_pcu->bssgp.bvc_timer, secs, 0);
 		return;
 	}
@@ -993,7 +993,7 @@
 		LOGP(DBSSGP, LOGL_INFO, "Sending unblock on BVCI %d\n",
 			the_pcu->bssgp.bctx->bvci);
 		bssgp_tx_bvc_unblock(the_pcu->bssgp.bctx);
-		secs = osmo_tdef_get(the_pcu->T_defs, 1, OSMO_TDEF_S, -1);
+		secs = osmo_tdef_get(the_pcu->T_defs, -101, OSMO_TDEF_S, -1);
 		osmo_timer_schedule(&the_pcu->bssgp.bvc_timer, secs, 0);
 		return;
 	}