selinux: cleanup dentry and inodes on error in selinuxfs

[ Upstream commit 7e4237fa ]

If the resource requested by d_alloc_name is not added to the linked
list through d_add, then dput needs to be called to release the
subsequent abnormal branch to avoid resource leakage.

Add missing dput to selinuxfs.c

Signed-off-by: nixiaoming <nixiaoming@huawei.com>
[PM: tweak the subject line]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>