jffs2: unlock f->sem on error in jffs2_new_inode()

jffs2: unlock f->sem on error in jffs2_new_inode()

If jffs2_new_inode() succeeds, it returns with f->sem held, and the caller
is responsible for releasing the lock.  If it fails, it still returns with
the lock held, but the caller won't release the lock, which will lead to
deadlock.

Fix it by releasing the lock in jffs2_new_inode() on error.

Signed-off-by: Wang Guoli <andy.wangguoli@huawei.com>
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Wang Guoli <andy.wangguoli@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
[Brian: not marked for stable; no one observed deadlock, and I don't
        think it can happen here]
Signed-off-by: Brian Norris <computersforpeace@gmail.com>