d3d12: Use IID_PPV_ARGS instead of __uuidof

d3d12: Use IID_PPV_ARGS instead of __uuidof

We've been inconsistent between IID_PPV_ARGS,
__uuidof(var), and __uuidof(type). Since Linux doesn't
support the latter of these, they need to be changed.
While we're at it, switch all __uuidof to the more terse
IIV_PPV_ARGS option.

Reviewed-by: Erik Faye-Lund <erik.faye-lund@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7937>