panfrost: Adds Bifrost shader disassembler utility

panfrost: Adds Bifrost shader disassembler utility

This code is stable and can live upstream independently while the rest
of the Bifrost stack comes up.

v2: Added a verbose flag to hide away some of the more verbose features
that nobody really needs

[The Bifrost disassembler is written by Connor Abbott, Lyude Paul, and
Ryan Houdek.]

Reviewed-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>