tbf_ul_fsm: Fix wrong cast

Change-Id: I6c68e85cfa7ca8d08ed7c851e31831c30772012e
diff --git a/src/tbf_ul_fsm.c b/src/tbf_ul_fsm.c
index 49849ba..7dff359 100644
--- a/src/tbf_ul_fsm.c
+++ b/src/tbf_ul_fsm.c
@@ -43,7 +43,7 @@
 #define tbf_ul_fsm_state_chg(fi, NEXT_STATE) \
 	osmo_tdef_fsm_inst_state_chg(fi, NEXT_STATE, \
 				     tbf_ul_fsm_timeouts, \
-				     tbf_ms(((struct tbf_dl_fsm_ctx *)(fi->priv))->tbf)->bts->T_defs_bts, \
+				     tbf_ms(((struct tbf_ul_fsm_ctx *)(fi->priv))->tbf)->bts->T_defs_bts, \
 				     -1)
 
 static void mod_ass_type(struct tbf_ul_fsm_ctx *ctx, uint8_t t, bool set)