D3D/DXShader: Remove duplicate GetByteCode function

This is already provided in the base class, which performs the same
exact behavior. Given the function in the base class isn't virtual, this
also essentially resolves an instance of shadowing.

Source/Core/VideoBackends/D3D/DXShader.h

@@ -16,8 +16,6 @@ public:
   DXShader(ShaderStage stage, BinaryData bytecode, ID3D11DeviceChild* shader);
   ~DXShader() override;
 
-  const BinaryData& GetByteCode() const { return m_bytecode; }
-
   ID3D11VertexShader* GetD3DVertexShader() const;
   ID3D11GeometryShader* GetD3DGeometryShader() const;
   ID3D11PixelShader* GetD3DPixelShader() const;