e1000e: potentially incorrect return for e1000_init_hw_ich8lan

In the unlikely event that e1000_setup_link_ich8lan() returns an error,
the returned error code value is not propagated to the caller of
e1000_init_hw_ich8lan().

Signed-off-by: Bruce Allan <bruce.w.allan@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>