gfxstream: use util/libsync

Gets rid of some #ifdefs.

Acked-by: Yonggang Luo <luoyonggang@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/31548>

src/gfxstream/guest/platform/linux/LinuxSync.cpp

@@ -2,25 +2,19 @@
  * Copyright 2023 Google
  * SPDX-License-Identifier: MIT
  */
+
 #include "LinuxSync.h"
 
-#if defined(__ANDROID__)
-#include <sync/sync.h>
-#endif
 #include <unistd.h>
 
+#include "util/libsync.h"
+
 namespace gfxstream {
 
 LinuxSyncHelper::LinuxSyncHelper() {}
 
 int LinuxSyncHelper::wait(int syncFd, int timeoutMilliseconds) {
-#if defined(__ANDROID__)
     return sync_wait(syncFd, timeoutMilliseconds);
-#else
-    (void)syncFd;
-    (void)timeoutMilliseconds;
-    return -1;
-#endif
 }
 
 int LinuxSyncHelper::dup(int syncFd) { return ::dup(syncFd); }