net: phy: mxl-gpy: add missing support for TRIGGER_NETDEV_LINK_10

The PHY also support 10MBit/s links as well as the corresponding link
indication trigger to be offloaded. Add TRIGGER_NETDEV_LINK_10 to the
supported triggers.

Signed-off-by: Daniel Golle <daniel@makrotopia.org>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://patch.msgid.link/cc5da0a989af8b0d49d823656d88053c4de2ab98.1728057367.git.daniel@makrotopia.org


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