ixgbe: Merge watchdog functionality into service task

This patch is meant to merge the functionality of the ixgbe watchdog task
into the service task.  By doing this all link state functionality will be
controlled by a single task.  As a result the reliability of the interface
will be improved as the likelihood of any race conditions is further
reduced.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>