Bindgen 0.65.1 no longer supports size_t-is-usize

The flag has been a default, and now is not accepted.

Test: Treehugger, m rust
Bug: 279198502
Bug: 276464273
Change-Id: Ifdf9968bfcdb278f73cf31ab68bc6b488b39436b
diff --git a/libstats/pull_rust/Android.bp b/libstats/pull_rust/Android.bp
index 85a38f8..4609e6b 100644
--- a/libstats/pull_rust/Android.bp
+++ b/libstats/pull_rust/Android.bp
@@ -28,7 +28,6 @@
     ],
     source_stem: "bindings",
     bindgen_flags: [
-        "--size_t-is-usize",
         "--allowlist-function=AStatsEventList_addStatsEvent",
         "--allowlist-function=AStatsEvent_.*",
         "--allowlist-function=AStatsManager_.*",