panfrost: add a decoder for panthor coredumps

I will update this MR shortly with a link to the kernel submission. I will possibly add some example dump file so it's easier to test this tool without having to patch the kernel as well.

Please note that this depends on !30594 for the memstream changes. It also proves that these changes are working.

edit: kernel patches at https://lore.kernel.org/all/20240813210555.607641-1-daniel.almeida@collabora.com/

branch at https://gitlab.collabora.com/dwlsalmeida/for-upstream/-/tree/panthor-devcoredump?ref_type=heads