Merge patch "efs: Remove EFS"

The kernel EFS code has been unmaintained for over twenty years.
It was superseded on IRIX around thirty years ago.  I haven't seen an
EFS filesystem in the wild since 1999.  Userspace tools to read EFS
filesystems exist, such as https://github.com/jkbenaim/efsextract

There's no benefit to keeping this filesystem in the kernel, and it only
increases the maintenance burden for tree-wide changes.

* patches from https://patch.msgid.link/20260618211822.3599089-1-willy@infradead.org:
  efs: Remove EFS

Link: https://patch.msgid.link/20260618211822.3599089-1-willy@infradead.org
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>