ixgbe: Combine SFP and multi-speed fiber task into single service task

This change is meant to address several race conditions with multi-speed
fiber SFP+ modules in 82599 adapters.  Specifically issues have been seen
in which both the SFP configuration and the multi-speed fiber configuration
are running simultaneously which will result in the device getting into an
erroneous link down state.

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