[apple] Fix build with newer libc++

Using `return mPtr` without a `*` works too, but it looks lie these
methods are unused, so just remove them.

Bug: chromium:1454568
Change-Id: Ie4441ac611787765e354480561e6a0e25aefa159
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/4631841
Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>
Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>
Auto-Submit: Nico Weber <thakis@chromium.org>
diff --git a/src/compiler/translator/TranslatorMetalDirect/Reference.h b/src/compiler/translator/TranslatorMetalDirect/Reference.h
index 4b5d86c..d53c809 100644
--- a/src/compiler/translator/TranslatorMetalDirect/Reference.h
+++ b/src/compiler/translator/TranslatorMetalDirect/Reference.h
@@ -20,7 +20,7 @@
     Ref(T &ref) : mPtr(&ref) {}
 
     Ref &operator=(const Ref &) = default;
-    Ref &operator=(Ref &&) = default;
+    Ref &operator=(Ref &&)      = default;
 
     bool operator==(const Ref &other) const { return *mPtr == *other.mPtr; }
     bool operator!=(const Ref &other) const { return *mPtr != *other.mPtr; }
@@ -35,9 +35,6 @@
     operator T &() { return *mPtr; }
     operator T const &() const { return *mPtr; }
 
-    operator T *() { return *mPtr; }
-    operator T const *() const { return *mPtr; }
-
   private:
     T *mPtr;
 };