This fixes an assertion in iris_disk_cache_init() when the initialization goes through drm_create_adapter(), which lives in d3dadapter9.so. In this case build_id_find_nhdr_for_addr() fails and returns NULL, since the shared library does not include a build ID.
The issue can be reproduced with an iris capable GPU and Xnine, while removing the shader cache prior to launching the application.
Fix this by doing the same as in 29ea92e6.
Fixes: 4756864c "iris: Start wiring up on-disk shader cache"