[d3d9] Fix return value for invalid backbuffer formats

This got changed when I saw that the auto depth stencil when set to an unavailable returns D3DERR_NOTAVAILABLE.
Turns out if the backbuffer is unavailable it returns D3DERR_INVALIDCALL...

Consistent...

Closes #1278

src/d3d9/d3d9_device.cpp

@@ -6470,7 +6470,7 @@ namespace dxvk {
         backBufferFmt,
         pPresentationParameters->Windowed)) {
         Logger::err("D3D9DeviceEx::ResetSwapChain: Unsupported backbuffer format.");
-        return D3DERR_NOTAVAILABLE;
+        return D3DERR_INVALIDCALL;
       }
     }