Fix typos in comments documenting fsm st chg macro

Change-Id: I8f1cef5810c84441f7d6d2fbe5b3106e0ae71b69
diff --git a/src/tbf_fsm.h b/src/tbf_fsm.h
index 1874bc3..9d2919d 100644
--- a/src/tbf_fsm.h
+++ b/src/tbf_fsm.h
@@ -57,7 +57,7 @@
 };
 
 extern const struct osmo_tdef_state_timeout tbf_fsm_timeouts[32];
-/* Transition to a state, using the T timer defined in assignment_fsm_timeouts.
+/* Transition to a state, using the T timer defined in tbf_fsm_timeouts.
  * The actual timeout value is in turn obtained from conn->T_defs.
  * Assumes local variable fi exists. */
 #define tbf_fsm_state_chg(fi, NEXT_STATE) \