avutil/hwcontext_d3d11va: prefer DXGI 1.1 factory when available

A lot of modern stuff straight up fails on the old 1.0 factory, which is
masked by the fact that it's only used when an explicit adapter is
specified.

libavutil/hwcontext_d3d11va.c

@@ -62,6 +62,8 @@ static av_cold void load_functions(void)
         return;
 
     mD3D11CreateDevice = (PFN_D3D11_CREATE_DEVICE) GetProcAddress(d3dlib, "D3D11CreateDevice");
+    mCreateDXGIFactory = (PFN_CREATE_DXGI_FACTORY) GetProcAddress(dxgilib, "CreateDXGIFactory1");
+    if (!mCreateDXGIFactory)
         mCreateDXGIFactory = (PFN_CREATE_DXGI_FACTORY) GetProcAddress(dxgilib, "CreateDXGIFactory");
 #else
     // In UWP (which lacks LoadLibrary), CreateDXGIFactory isn't available,