d3d11device: Enhance format enumeration and debugging

d3d11device: Enhance format enumeration and debugging

* Enhance debug log to print human readable D3D11_FORMAT_SUPPORT flags
  value, instead of packed numeric flagset value.
* Only device supported format will be added to format table.
  Depending on device feature level (i.e., D3D9 feature devices),
  16bits formats will not be supported. Although there might be formats
  we deinfed but not supported, it will not be a major issue in practice
  since our D3D11 implementation does not support legacy devices already
  (known limitation) and also old d3dvideosink will be promoted in that case.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/2441>