amd-xgbe: Convert to using the new link mode settings

Convert from using the old u32 supported, advertising, etc. link settings
to the new link mode settings that support bit positions / settings
greater than 32 bits.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: David S. Miller <davem@davemloft.net>