scsi: sas: Convert timers to use timer_setup()

scsi: sas: Convert timers to use timer_setup()

In preparation for unconditionally passing the struct timer_list pointer to
all timer callbacks, switch to using the new timer_setup() and from_timer()
to pass the timer pointer explicitly. This requires adding a pointer to
hold the timer's target task, as there isn't a link back from slow_task.

Cc: John Garry <[email protected]>
Cc: "James E.J. Bottomley" <[email protected]>
Cc: "Martin K. Petersen" <[email protected]>
Cc: Jack Wang <[email protected]>
Cc: [email protected]
Cc: Jens Axboe <[email protected]>
Cc: Hannes Reinecke <[email protected]>
Cc: Johannes Thumshirn <[email protected]>
Cc: Benjamin Block <[email protected]>
Cc: Baoyou Xie <[email protected]>
Cc: Wei Yongjun <[email protected]>
Cc: [email protected]
Signed-off-by: Kees Cook <[email protected]>
Reviewed-by: Martin K. Petersen <[email protected]>
Acked-by: John Garry <[email protected]> # for hisi_sas part
Tested-by: John Garry <[email protected]> # basic sanity test for hisi_sas
Reviewed-by: Jack Wang <[email protected]>