xfs: delete unnecessary NULL checks

mainline inclusion
from mainline-v5.19-rc5
commit 3f52e016
category: bugfix
bugzilla: 187164, https://gitee.com/openeuler/kernel/issues/I4KIAO
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=3f52e016af600982989b5dee958d313c52483c92



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These NULL check are no long needed after commit 2ed5b09b ("xfs:
make inode attribute forks a permanent part of struct xfs_inode").

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Long Li <leo.lilong@huawei.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Signed-off-by: Jialin Zhang <zhangjialin11@huawei.com>