Remove unused EventFlag constructor am: 6a548ad593

Original change: https://android-review.googlesource.com/c/platform/system/libfmq/+/1792490

Change-Id: I44fdcee1fad638961bac658e8315c98872cec557
tree: 851f3fc590084e99ecb64c025d80e6428e4a70d5
  1. base/
  2. benchmarks/
  3. include/
  4. tests/
  5. Android.bp
  6. EventFlag.cpp
  7. FmqInternal.cpp
  8. OWNERS
  9. PREUPLOAD.cfg
  10. TEST_MAPPING