atlx: timer cleanup

Do some cleanup on timer usage in this driver:
  * Use round_jiffies to align wakeups and reduce power.
  * Remove atl1_watchdog which does nothing but rearm itself
  * Use setup_timer() function

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>