RDMA/rtrs: Add missing deinit() call

In the Linux kernel, the following vulnerability has been resolved:

RDMA/rtrs: Add missing deinit() call

A warning is triggered when repeatedly connecting and disconnecting the rnbd: list_add corruption. prev->next should be next (ffff88800b13e480), but was ffff88801ecd1338. (prev=ffff88801ecd1340). WARNING: CPU: 1 PID: 36562 at lib/list_debug.c:32 __list_add_valid_or_report+0x7f/0xa0 Workqueue: ib_cm cm_work_handler [ib_cm] RIP: 0010:__list_add_valid_or_report+0x7f/0xa0 ? __list_add_valid_or_report+0x7f/0xa0 ib_register_event_handler+0x65/0x93 [ib_core] rtrs_srv_ib_dev_init+0x29/0x30 [rtrs_server] rtrs_ib_dev_find_or_add+0x124/0x1d0 [rtrs_core] __alloc_path+0x46c/0x680 [rtrs_server] ? rtrs_rdma_connect+0xa6/0x2d0 [rtrs_server] ? rcu_is_watching+0xd/0x40 ? __mutex_lock+0x312/0xcf0 ? get_or_create_srv+0xad/0x310 [rtrs_server] ? rtrs_rdma_connect+0xa6/0x2d0 [rtrs_server] rtrs_rdma_connect+0x23c/0x2d0 [rtrs_server] ? __lock_release+0x1b1/0x2d0 cma_cm_event_handler+0x4a/0x1a0 [rdma_cm] cma_ib_req_handler+0x3a0/0x7e0 [rdma_cm] cm_process_work+0x28/0x1a0 [ib_cm] ? _raw_spin_unlock_irq+0x2f/0x50 cm_req_handler+0x618/0xa60 [ib_cm] cm_work_handler+0x71/0x520 [ib_cm]

Commit 667db86bcbe8 ("RDMA/rtrs: Register ib event handler") introduced a new element .deinit but never used it at all. Fix it by invoking the deinit() to appropriately unregister the IB event handler.