[d3d9] Remove leftover GetWindowRect

This is already done for us.

src/d3d9/d3d9_swapchain.cpp

@@ -1019,9 +1019,6 @@ namespace dxvk {
   HRESULT D3D9SwapChainEx::EnterFullscreenMode(
           D3DPRESENT_PARAMETERS* pPresentParams,
     const D3DDISPLAYMODEEX*      pFullscreenDisplayMode) {    
-    // Find a display mode that matches what we need
-    ::GetWindowRect(m_window, &m_windowState.rect);
-      
     if (FAILED(ChangeDisplayMode(pPresentParams, pFullscreenDisplayMode))) {
       Logger::err("D3D9: EnterFullscreenMode: Failed to change display mode");
       return D3DERR_INVALIDCALL;