pan/bi: Track M values of disassembled constants

We'll want to route these values from the clause itself to the source
dump in order to disassemble modified embedded constants.

Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6793>
3 files changed