AMD doesn't make LAN Network drivers. Need to go to your Motherboard's Support site and download it from there. Or if you know the company chip that operates the LAN Network feature on your motherboard, you can go to their support site and download the proper driver.
As an Example:
My Asus Motherboard uses a RealTek Lan Network chip. So I can either go to Asus Support site and download the LAN Network driver from there or go to Reatek and download the LAN Network driver from their website.