pciehp: clear p_slot->work.data after powering off a slot

hulk inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I8Z2JH



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Powering off nvme device may cause a Data Link Layer State Changed event.
This event results in re-enabling the device. In order to fix this issue,
clear out the Presence Detect Changed and Data Link Layer State Changed
events in p_slot->work.data.

Fixes: 8f7e5053 ("pciehp: do not wake up irq_thread for sysfs operation")
Signed-off-by: Jialin Zhang <zhangjialin11@huawei.com>