xfs: factor out xfs_defer_pending_abort

Offering: HULK
hulk inclusion
category: bugfix
bugzilla: 188865, https://gitee.com/openeuler/kernel/issues/I76JSK



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Factor out xfs_defer_pending_abort() from xfs_defer_trans_abort(), which
not use transaction parameter, so it can be used after the transaction
life cycle.

Signed-off-by: Long Li <leo.lilong@huawei.com>