samples: remove boards folder since don't need any more

2 job 于samples/remove_boards in 6 minute 和 57 second (queued for 2 second)
状态 作业 ID 名称 覆盖率
  Ztest
已通过 #43413
zgsz-02 generic
ztest_build_only

00:04:54

已通过 #43414
zgsz-03 with-device
ztest_device_test

00:04:13