libbsc: Call lchan_free in the timeout callbacks

This makes sure that the lchans can be used again. (state and type
are set to NONE)
diff --git a/openbsc/src/libbsc/abis_rsl.c b/openbsc/src/libbsc/abis_rsl.c
index 8a326de..4b30763 100644
--- a/openbsc/src/libbsc/abis_rsl.c
+++ b/openbsc/src/libbsc/abis_rsl.c
@@ -185,7 +185,8 @@
 	LOGP(DRSL, LOGL_NOTICE, "%s Timeout during activation!\n",
 		gsm_lchan_name(lchan));
 
-	lchan->state = LCHAN_S_NONE;
+	rsl_lchan_set_state(lchan, LCHAN_S_NONE);
+	lchan_free(lchan);
 }
 
 static void lchan_deact_tmr_cb(void *data)
@@ -195,7 +196,8 @@
 	LOGP(DRSL, LOGL_NOTICE, "%s Timeout during deactivation!\n",
 		gsm_lchan_name(lchan));
 
-	lchan->state = LCHAN_S_NONE;
+	rsl_lchan_set_state(lchan, LCHAN_S_NONE);
+	lchan_free(lchan);
 }