net: stmmac: dwmac-socfpga: Add xgmac support for Agilex5

Add support for Agilex5 compatible value.

Signed-off-by: Mun Yew Tham <mun.yew.tham@altera.com>
Signed-off-by: Matthew Gerlach <matthew.gerlach@altera.com>
Link: https://patch.msgid.link/20250724154052.205706-5-matthew.gerlach@altera.com


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