rasterizer: Drop unused handler.

This virtual function is called in a very hot spot, and it does nothing.

If this kind of feature is required, please be more specific and add callbacks
in the switch statement within Maxwell3D::WriteReg. There is no point in having
another switch statement within the rasterizer.

src/video_core/engines/maxwell_3d.cpp

@@ -135,8 +135,6 @@ void Maxwell3D::WriteReg(u32 method, u32 value, u32 remaining_params) {
         break;
     }
 
-    rasterizer.NotifyMaxwellRegisterChanged(method);
-
     if (debug_context) {
         debug_context->OnEvent(Tegra::DebugContext::Event::MaxwellCommandProcessed, nullptr);
     }

src/video_core/rasterizer_interface.h

@@ -20,9 +20,6 @@ public:
     /// Clear the current framebuffer
     virtual void Clear() = 0;
 
-    /// Notify rasterizer that the specified Maxwell register has been changed
-    virtual void NotifyMaxwellRegisterChanged(u32 method) = 0;
-
     /// Notify rasterizer that all caches should be flushed to Switch memory
     virtual void FlushAll() = 0;
 

src/video_core/renderer_opengl/gl_rasterizer.cpp

@@ -527,8 +527,6 @@ void RasterizerOpenGL::DrawArrays() {
     state.Apply();
 }
 
-void RasterizerOpenGL::NotifyMaxwellRegisterChanged(u32 method) {}
-
 void RasterizerOpenGL::FlushAll() {}
 
 void RasterizerOpenGL::FlushRegion(VAddr addr, u64 size) {}

src/video_core/renderer_opengl/gl_rasterizer.h

@@ -45,7 +45,6 @@ public:
 
     void DrawArrays() override;
     void Clear() override;
-    void NotifyMaxwellRegisterChanged(u32 method) override;
     void FlushAll() override;
     void FlushRegion(VAddr addr, u64 size) override;
     void InvalidateRegion(VAddr addr, u64 size) override;