6.12 drm/amdgpu ip discovery for legacy asics

After 6.12.36, amdgpu on a picasso apu prints an error: "get invalid ip discovery binary signature".

Both with and without picasso_ip_discovery.bin from linux-firmware 20250708.

The error is avoided by backporting more ip discovery patches.

25f602fbbcc8 drm/amdgpu/discovery: use specific ip_discovery.bin for legacy asics 2f6dd741cdcd drm/amdgpu/ip_discovery: add missing ip_discovery fw

second is a fix for the first