[tint][sem] Remove unused member variable

Change-Id: I921c63c42cfcc849ca26d0d262f1a76bf77ea2aa
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/185361
Reviewed-by: dan sinclair <dsinclair@chromium.org>
Reviewed-by: James Price <jrprice@google.com>
Commit-Queue: Ben Clayton <bclayton@google.com>
diff --git a/src/tint/lang/wgsl/sem/variable.h b/src/tint/lang/wgsl/sem/variable.h
index 15ca981..bf97929 100644
--- a/src/tint/lang/wgsl/sem/variable.h
+++ b/src/tint/lang/wgsl/sem/variable.h
@@ -197,7 +197,6 @@
     const GlobalVariableAttributes& Attributes() const { return attributes_; }
 
   private:
-    std::optional<tint::BindingPoint> binding_point_;
     tint::OverrideId override_id_;
     UniqueVector<const GlobalVariable*, 4> transitively_referenced_overrides_;
     GlobalVariableAttributes attributes_;