Merge branch 'cpsw-bindings-for-5000m-fixed-link'

Siddharth Vadapalli says:

====================
CPSW Bindings for 5000M Fixed-Link

This series adds 5000M as a valid speed for fixed-link mode of operation
and also updates the CPSW bindings to evaluate fixed-link property. This
series is in the context of the following device-tree overlay which
enables USXGMII 5000M Fixed-link mode of operation with CPSW on TI's
J784S4 SoC:
https://github.com/torvalds/linux/blob/v6.15-rc1/arch/arm64/boot/dts/ti/k3-j784s4-evm-usxgmii-exp1-exp2.dtso
====================

Link: https://patch.msgid.link/20250411060917.633769-1-s-vadapalli@ti.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>