Avoid that aborting a command before it has been submitted onto
a workqueue triggers the following warning:

INFO: trying to register non-static key.
the code is fine but needs lockdep annotation.
turning off the locking correctness validator.
CPU: 3 PID: 46 Comm: kworker/u8:1 Not tainted 4.12.0-rc2-dbg+ #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.0.0-prebuilt.qemu-project.org 04/01/2014
Workqueue: tmr-iblock target_tmr_work [target_core_mod]
Call Trace:
 dump_stack+0x86/0xcf
 register_lock_class+0xe8/0x570
 __lock_acquire+0xa1/0x11d0
 lock_acquire+0x59/0x80
 flush_work+0x42/0x2b0
 __cancel_work_timer+0x10c/0x180
 cancel_work_sync+0xb/0x10
 core_tmr_lun_reset+0x352/0x740 [target_core_mod]
 target_tmr_work+0xd6/0x130 [target_core_mod]
 process_one_work+0x1ca/0x3f0
 worker_thread+0x49/0x3b0
 kthread+0x109/0x140
 ret_from_fork+0x31/0x40
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.com>
Cc: David Disseldorp <ddiss@suse.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>