Revert "NFSv4: Handle the special Linux file open access mode"

Revert "NFSv4: Handle the special Linux file open access mode"

BugLink: https://bugs.launchpad.net/bugs/1969107
[ Upstream commit ab0fc21bc7105b54bafd85bd8b82742f9e68898a ]

This reverts commit 44942b4e457beda00981f616402a1a791e8c616e.

After secondly opening a file with O_ACCMODE|O_DIRECT flags,
nfs4_valid_open_stateid() will dereference NULL nfs4_state when lseek().

Reproducer:
  1. mount -t nfs -o vers=4.2 $server_ip:/ /mnt/
  2. fd = open("/mnt/file", O_ACCMODE|O_DIRECT|O_CREAT)
  3. close(fd)
  4. fd = open("/mnt/file", O_ACCMODE|O_DIRECT)
  5. lseek(fd)

Reported-by: Lyu Tao <tao.lyu@epfl.ch>
Signed-off-by: ChenXiaoSong <chenxiaosong2@huawei.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
(cherry picked from commit 9f0c217469e84e71f7423bce64527c0b56bf9228)
Signed-off-by: Paolo Pisati <paolo.pisati@canonical.com>