egl/wgl: Delete unused variables/code
Fixes: 3415bf02 ("egl: Add a basic Windows driver") Suggested-by:Yonggang Luo <luoyonggang@gmail.com> Acked-by:
Daniel Stone <daniels@collabora.com> Acked-by:
Mike Blumenkrantz <michael.blumenkrantz@gmail.com> Acked-by:
Sidney Just <justsid@x-plane.com> Acked-by:
Jason Ekstrand <jason.ekstrand@collabora.com> Tested-by:
Yonggang Luo <luoyonggang@gmail.com> Part-of: <mesa/mesa!12964> (cherry picked from commit efd2ae6c)