Input: implement proper timer rounding for polled devices

Rounding doesn't matter for the first tick, but we want
succeeding ticks to be aligned on second boundary if poll
interval is large enough.

Also: cancel_rearming_delayed_workqueue is marked as obsolete
in workqueue.h so use cancel_delayed_work_sync.

Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Acked-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>