scsi: message: mptlan: Fix use after free bug in mptlan_remove() due to race condition

In the Linux kernel, the following vulnerability has been resolved: scsi: message: mptlan: Fix use after free bug in mptlan_remove() due to race condition mptlan_probe() calls mpt_register_lan_device() which initializes the &priv->post_buckets_task workqueue. A call to mpt_lan_wake_post_buckets_task() will subsequently start the work. During driver unload in mptlan_remove() the following race may occur: CPU0 CPU1 |mpt_lan_post_receive_buckets_work() mptlan_remove() | free_netdev() | kfree(dev); | | | dev->mtu | //use Fix this by finishing the work prior to cleaning up in mptlan_remove(). [mkp: we really should remove mptlan instead of attempting to fix it]