jffs2: move jffs2_init_inode_info() just after allocating inode

hulk inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I8TC11


CVE: NA

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

After commit 4fdcfab5 ("jffs2: fix use-after-free on symlink
traversal"), it expose a freeing uninitialized memory problem due to
this commit move the operaion of freeing f->target to
jffs2_i_callback(), which may not be initialized in some error path of
allocating jffs2 inode (eg: jffs2_iget()->iget_locked()->
destroy_inode()->..->jffs2_i_callback()->kfree(f->target)).

Fix this by initialize the jffs2_inode_info just after allocating it.

Signed-off-by: zhangyi (F) <yi.zhang@huawei.com>

Conflicts:
	fs/jffs2/super.c

Signed-off-by: ZhaoLong Wang <wangzhaolong1@huawei.com>