message: Give error if attempting to use FA with OpenMP
diff: @@ -84,7 +84,7 @@ BilinearForm::BilinearForm (FiniteElementSpace * f,
  switch (assembly)
  {
  case AssemblyLevel::FULL:
  - if (Device::UsingDevice())
  + if (Device::UsingDevice() || Device::UsingOmp())
  {
  mfem_error("Full assembly not supported yet in device mode!");
  }
  