Mask unused-parameter warnings in static flatbuffer codegen

Empty flatbuffer tables would result in unused parameters; just hide
those warnings.

Change-Id: Ic3d6f21d937b1056b493efc7bed33f05e750495d
Signed-off-by: James Kuszmaul <jabukuszmaul+collab@gmail.com>
diff --git a/aos/flatbuffers/static_flatbuffers.cc b/aos/flatbuffers/static_flatbuffers.cc
index e3130bb..6dceb27 100644
--- a/aos/flatbuffers/static_flatbuffers.cc
+++ b/aos/flatbuffers/static_flatbuffers.cc
@@ -599,7 +599,7 @@
   // after a call to FromFlatbufferObject().
   // This is a deep copy, and will call FromFlatbufferObject on
   // any constituent objects.
-  [[nodiscard]] bool FromFlatbuffer(const Flatbuffer::NativeTableType &other) {
+  [[nodiscard]] bool FromFlatbuffer([[maybe_unused]] const Flatbuffer::NativeTableType &other) {
     Clear();
     %s
     return true;
@@ -653,7 +653,7 @@
   // returning true on success.
   // This is a deep copy, and will call FromFlatbuffer on any constituent
   // objects.
-  [[nodiscard]] bool FromFlatbuffer(const Flatbuffer &other) {
+  [[nodiscard]] bool FromFlatbuffer([[maybe_unused]] const Flatbuffer &other) {
     Clear();
     %s
     return true;