The management port on an Edgecore AS7712-32 switch uses an igb MAC, but
it uses a BCM54616 PHY. Without a patch like this, loading the igb
module produces dmesg output like this:
[ 3.439125] igb: Copyright (c) 2007-2014 Intel Corporation.
[ 3.439866] igb: probe of 0000:00:14.0 failed with error -2
Signed-off-by: John W Linville <linville@tuxdriver.com> Cc: Jeff Kirsher <jeffrey.t.kirsher@intel.com> Tested-by: Aaron Brown <aaron.f.brown@intel.com> Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>