ixgbe: fix disabling of Tx laser at probe

register_netdev() calls ndo_set_features() which may result in HW reset
which in turn will bring the laser back up.

This patch moves ixgbe_laser_tx_disable() below register_netdev()
in ixgbe_probe() to make sure laser is shut off on load.

Signed-off-by: Emil Tantilov <emil.s.tantilov@intel.com>
Tested-by: Phil Schmitt <phillip.j.schmitt@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>