Use -Werror in frameworks/av/media/libaaudio/examples.

Bug: 66996870
Test: build with WITH_TIDY=1
Change-Id: I758a62b26d3c66727963083fa479b995f6696c87
diff --git a/media/libaaudio/examples/loopback/Android.bp b/media/libaaudio/examples/loopback/Android.bp
index 2b624a8..fa8fdc9 100644
--- a/media/libaaudio/examples/loopback/Android.bp
+++ b/media/libaaudio/examples/loopback/Android.bp
@@ -2,6 +2,7 @@
     name: "aaudio_loopback",
     gtest: false,
     srcs: ["src/loopback.cpp"],
+    cflags: ["-Wall", "-Werror"],
     shared_libs: ["libaaudio"],
     header_libs: ["libaaudio_example_utils"],
 }