Fix NDK libsync to match ndk/sync.h

The header names were changed during review, but the library map file
wasn't updated.

Bug: 62229958
Test: CtsGraphicsTestCases:android.graphics.cts.SyncTest
Merged-In: Ie5955865667b35067f1ee209933f159f170419cd
Change-Id: Ie5955865667b35067f1ee209933f159f170419cd
(cherry picked from commit 59d9ee5d)