drivers/input: remove nxsig_notification when signal support is disabled

When all signals are disabled, nxsig_notification is not available and
should not be invoked. Remove the call to avoid build and runtime issues
in no-signal configurations.

Signed-off-by: Chengdong Wang <wangchengdong@lixiang.com>

drivers/input/button_upper.c

@@ -85,9 +85,11 @@ struct btn_open_s
 
   /* Button event notification information */
 
+#ifndef CONFIG_DISABLE_ALL_SIGNALS
   pid_t bo_pid;
   struct btn_notify_s bo_notify;
   struct sigwork_s bo_work;
+#endif
 
   /* Poll event information */
 
@@ -297,6 +299,7 @@ static void btn_sample(wdparm_t arg)
 
       /* Have any signal events occurred? */
 
+#ifndef CONFIG_DISABLE_ALL_SIGNALS
       if ((press & opriv->bo_notify.bn_press)     != 0 ||
           (release & opriv->bo_notify.bn_release) != 0)
         {
@@ -306,6 +309,7 @@ static void btn_sample(wdparm_t arg)
           nxsig_notification(opriv->bo_pid, &opriv->bo_notify.bn_event,
                              SI_QUEUE, &opriv->bo_work);
         }
+#endif
     }
 
   priv->bu_sample = sample;