nvme-rdma: Avoid double freeing of async event data

nvme-rdma: Avoid double freeing of async event data

[ Upstream commit 9134ae2a2546cb96abddcd4469a79c77ee3a4480 ]

The timeout of identify cmd, which is invoked as part of admin queue
creation, can result in freeing of async event data both in
nvme_rdma_timeout handler and error handling path of
nvme_rdma_configure_admin queue thus causing NULL pointer reference.
Call Trace:
 ? nvme_rdma_setup_ctrl+0x223/0x800 [nvme_rdma]
 nvme_rdma_create_ctrl+0x2ba/0x3f7 [nvme_rdma]
 nvmf_dev_write+0xa54/0xcc6 [nvme_fabrics]
 __vfs_write+0x1b/0x40
 vfs_write+0xb2/0x1b0
 ksys_write+0x61/0xd0
 __x64_sys_write+0x1a/0x20
 do_syscall_64+0x60/0x1e0
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reviewed-by: Roland Dreier <roland@purestorage.com>
Reviewed-by: Max Gurtovoy <maxg@mellanox.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Prabhath Sajeepa <psajeepa@purestorage.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>