dt-bindings: net: Document support for Aeonsemi PHYs

dt-bindings: net: Document support for Aeonsemi PHYs

Add Aeonsemi PHYs and the requirement of a firmware to correctly work.
Also document the max number of LEDs supported and what PHY ID expose
when no firmware is loaded.

Supported PHYs AS21011JB1, AS21011PB1, AS21010JB1, AS21010PB1,
AS21511JB1, AS21511PB1, AS21510JB1, AS21510PB1, AS21210JB1,
AS21210PB1 that all register with the PHY ID 0x7500 0x9410 on C45
registers before the firmware is loaded.

Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
Link: https://patch.msgid.link/20250517201353.5137-7-ansuelsmth@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>