Use -Werror in device/linaro/hikey

* Use -Wno-error= for existing warnings, to fix later.

Bug: 66996870
Test: build with WITH_TIDY=1
Change-Id: Ib846e75a68e914dfc3c90cbc89e071f22dff013d
diff --git a/bluetooth/Android.bp b/bluetooth/Android.bp
index 142ced2..ab128ee 100644
--- a/bluetooth/Android.bp
+++ b/bluetooth/Android.bp
@@ -25,6 +25,13 @@
         "hci_protocol.cc",
         "service.cc",
     ],
+    cflags: [
+        "-Wall",
+        "-Werror",
+        "-Wno-error=unused-const-variable",
+        "-Wno-error=unused-function",
+        "-Wno-error=unused-lambda-capture",
+    ],
     shared_libs: [
         "android.hardware.bluetooth@1.0",
         "libbase",