system-linux: add autoneg and link-partner output

system-linux: add autoneg and link-partner output

This adds an array that contains the link modes advertised by the other device and also
indicates whether auto negotiation is true or false.

link-partner may or may not be populated depending on hardware, driver and/or settings.

Signed-off-by: Joe Holden <jwh@zorins.co.uk>
Signed-off-by: Hans Dedecker <dedeckeh@gmail.com>