Removes const qualification for two methods in TargetDataLowering.

src/IceTargetLowering.h

Index: src/IceTargetLowering.h
diff --git a/src/IceTargetLowering.h b/src/IceTargetLowering.h
index 069b49e453db7237a274c4d4f23b33f3f1652ef0..66e663b1030834b6b3270e1172495c5e0697d9a7 100644
--- a/src/IceTargetLowering.h
+++ b/src/IceTargetLowering.h
@@ -380,9 +380,8 @@ public:
   static std::unique_ptr<TargetDataLowering> createLowering(GlobalContext *Ctx);
   virtual ~TargetDataLowering();
 
-  virtual void
-  lowerGlobals(std::unique_ptr<VariableDeclarationList> Vars) const = 0;
-  virtual void lowerConstants() const = 0;
+  virtual void lowerGlobals(std::unique_ptr<VariableDeclarationList> Vars) = 0;
+  virtual void lowerConstants() = 0;
 
 protected:
   explicit TargetDataLowering(GlobalContext *Ctx) : Ctx(Ctx) {}