block: swim3: 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.

Cc: Jens Axboe <axboe@kernel.dk>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Arvind Yadav <arvind.yadav.cs@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>