Add return status check

Check for the return status to avoid compiler emitting [[nodiscard]]
error.

Test: m checkbuild
Bug: 126457671
Change-Id: I733e58bacd363b1d2332ed138cad04d7d96819fc
diff --git a/tests/benchmarks/bpf_benchmark.cpp b/tests/benchmarks/bpf_benchmark.cpp
index 9146923..2c1ed1e 100644
--- a/tests/benchmarks/bpf_benchmark.cpp
+++ b/tests/benchmarks/bpf_benchmark.cpp
@@ -32,7 +32,9 @@
 };
 
 BENCHMARK_DEFINE_F(BpfBenchMark, MapWriteNewEntry)(benchmark::State& state) {
-    for (auto _ : state) mBpfTestMap.writeValue(state.range(0), state.range(0), BPF_NOEXIST);
+    for (auto _ : state) {
+        expectOk(mBpfTestMap.writeValue(state.range(0), state.range(0), BPF_NOEXIST));
+    }
 }
 
 BENCHMARK_DEFINE_F(BpfBenchMark, MapUpdateEntry)(benchmark::State& state) {