net: phy: aquantia: search for firmware-name in fwnode

Allow the firmware name of an Aquantia PHY alternatively be provided by the
property "firmware-name" of a swnode. This software node may be provided by
the MAC or MDIO driver.

Signed-off-by: Hans-Frieder Vogt <hfdevel@gmx.net>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://patch.msgid.link/20250322-tn9510-v3a-v7-3-672a9a3d8628@gmx.net


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