[S390] cio: use INIT_WORK to initialize struct work.

Use INIT_WORK to initialize struct work and don't initialize a
struct work partial by explicitly initializing its private structures.
Fixes the following lockdep bug because no key was assigned:

INFO: trying to register non-static key.
the code is fine but needs lockdep annotation.
turning off the locking correctness validator.
0000000001f07bb8 0000000001f07bf8 0000000000000002 0000000000000000
       0000000001f07c98 0000000001f07c10 0000000001f07c10 0000000000015406
       0000000000000000 0000000000000002 0000000000000000 0000000000000000
       0000000001f07bf8 000000000000000c 0000000001f07bf8 0000000001f07c68
       000000000039ae60 0000000000015406 0000000001f07bf8 0000000001f07c48
Call Trace:
([<0000000000015376>] show_trace+0xda/0x104)
 [<0000000000015460>] show_stack+0xc0/0xf8
 [<00000000000154c6>] dump_stack+0x2e/0x3c
 [<000000000006a71e>] __lock_acquire+0x47e/0x11a0
 [<000000000006b4f0>] lock_acquire+0xb0/0xd8
 [<00000000000555a6>] run_workqueue+0x1aa/0x24c
 [<00000000000556de>] worker_thread+0x96/0xf4
 [<000000000005c210>] kthread+0x90/0xb4
 [<000000000001947a>] kernel_thread_starter+0x6/0xc
 [<0000000000019474>] kernel_thread_starter+0x0/0xc

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>