CVE-2026-23421

In the Linux kernel, the following vulnerability has been resolved:

drm/xe/configfs: Free ctx_restore_mid_bb in release

ctx_restore_mid_bb memory is allocated in wa_bb_store(), but
xe_config_device_release() only frees ctx_restore_post_bb.

Free ctx_restore_mid_bb[0].cs as well to avoid leaking the allocation
when the configfs device is removed.

(cherry picked from commit a235e7d0098337c3f2d1e8f3610c719a589e115f)