jffs2: reset pino_nlink to 0 when inode creation failed

hulk inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I8TYET
CVE: NA

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So jffs2_do_clear_inode() could mark all flash nodes used by
the inode as obsolete and GC procedure will reclaim these
flash nodes, else these flash spaces will not be reclaimable
forever.

Link: http://lists.infradead.org/pipermail/linux-mtd/2019-February/087763.html


Signed-off-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: ZhaoLong Wang <wangzhaolong1@huawei.com>