Mark function unused.

Mark the TypeBuiltinStruct method as unused in the IR encoder.

Change-Id: Id65a596af44a7c73fccd742c083d22554adae975
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/226635
Commit-Queue: James Price <jrprice@google.com>
Auto-Submit: dan sinclair <dsinclair@chromium.org>
Reviewed-by: James Price <jrprice@google.com>
Commit-Queue: dan sinclair <dsinclair@chromium.org>

src/tint/lang/core/ir/binary/encode.cc

diff --git a/src/tint/lang/core/ir/binary/encode.cc b/src/tint/lang/core/ir/binary/encode.cc
index 83135c2..a9248aa 100644
--- a/src/tint/lang/core/ir/binary/encode.cc
+++ b/src/tint/lang/core/ir/binary/encode.cc
@@ -552,8 +552,8 @@
     //        subgroup_matrix_out.set_rows(subgroup_matrix_in->Rows());
     //    }
 
-    void TypeBuitinStruct(pb::Type& builtin_struct_out,
-                          const core::type::Struct* builtin_struct_in) {
+    [[maybe_unused]] void TypeBuitinStruct(pb::Type& builtin_struct_out,
+                                           const core::type::Struct* builtin_struct_in) {
         auto name = builtin_struct_in->Name().NameView();
         auto builtin = ParseBuiltinType(name);
         switch (builtin) {