io_uring/unix: drop usage of io_uring socket

stable inclusion
from stable-v5.10.214
commit 875f5fed30a182675f729f35bbd6ad62b52bd1ac
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9P06W
CVE: CVE-2023-52656

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=875f5fed30a182675f729f35bbd6ad62b52bd1ac



--------------------------------

Commit a4104821ad651d8a0b374f0b2474c345bbb42f82 upstream.

Since we no longer allow sending io_uring fds over SCM_RIGHTS, move to
using io_is_uring_fops() to detect whether this is a io_uring fd or not.
With that done, kill off io_uring_get_socket() as nobody calls it
anymore.

This is in preparation to yanking out the rest of the core related to
unix gc with io_uring.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>

Conflicts:
	include/linux/io_uring.h
	include/linux/fs.h
	fs/io_uring.c
	io_uring/io_uring.c
Signed-off-by: Zizhi Wo <wozizhi@huawei.com>