net: phy: Add BaseT1 auto-negotiation constants

Added constants for advertising 100BT1 and 1000BT1 in register BASE-T1
auto-negotiation advertisement register [31:16] (Register 7.515)

Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Dimitri Fedrau <dima.fedrau@gmail.com>
Link: https://lore.kernel.org/r/20240218075753.18067-2-dima.fedrau@gmail.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>