UPSTREAM: io_uring: import 5.15-stable io_uring

No upstream commit exists.

This imports the io_uring codebase from 5.15.85, wholesale. Changes
from that code base:

- Drop IOCB_ALLOC_CACHE, we don't have that in 5.10.
- Drop MKDIRAT/SYMLINKAT/LINKAT. Would require further VFS backports,
  and we don't support these in 5.10 to begin with.
- sock_from_file() old style calling convention.
- Use compat_get_bitmap() only for CONFIG_COMPAT=y

Change-Id: I7ce5226d6b39763ffc246fd6357cece9aafd4b59
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit 788d0824)
Bug: 268174392
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>