Remove unused createEventFlag function am: 1390abc07c

Original change: https://android-review.googlesource.com/c/platform/system/libfmq/+/1792489

Change-Id: If89b1052b6fc424d4fc60e8f71f7e2f30fd1f4eb
tree: 8760f703cdec8d45bb1c1034f7663f91b45e9cf7
  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