sched/task/task_restart.c: Fix a compile error if CONFIG_DISABLE_SIGNALS defined.

sched/signal/sig_cleanup.c

@@ -58,7 +58,7 @@
 
 void nxsig_cleanup(FAR struct tcb_s *stcb)
 {
-  FAR sigq_t     *sigq;
+  FAR sigq_t *sigq;
 
   /* Deallocate all entries in the list of pending signal actions */
 
@@ -110,4 +110,3 @@ void nxsig_release(FAR struct task_group_s *group)
       nxsig_release_pendingsignal(sigpend);
     }
 }
-

sched/task/task_restart.c

@@ -158,10 +158,12 @@ int task_restart(pid_t pid)
   dq_rem((FAR dq_entry_t *)tcb, tasklist);
   tcb->cmn.task_state = TSTATE_TASK_INVALID;
 
+#ifndef CONFIG_DISABLE_SIGNALS
   /* Deallocate anything left in the TCB's signal queues */
 
   nxsig_cleanup((FAR struct tcb_s *)tcb);  /* Deallocate Signal lists */
   tcb->cmn.sigprocmask = NULL_SIGNAL_SET;  /* Reset sigprocmask */
+#endif
 
   /* Reset the current task priority  */