panfrost: Move format stringify to decode.c

Let's simplify pandecode before moving it around. We don't need to share
this routine right now, and we'll be generating it soon.

Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6196>
4 files changed