md: Convert timers to use timer_setup()

md: 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: Kent Overstreet <[email protected]>
Cc: Shaohua Li <[email protected]>
Cc: Alasdair Kergon <[email protected]>
Cc: Mike Snitzer <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Kees Cook <[email protected]>
Reviewed-by: Michael Lyle <[email protected]>
Reviewed-by: Mike Snitzer <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>