5.10.x deassert value too small for (some?) C3 board ETH PHY reset

As Stat_headcrabed hinted on the forum, it appears the deassert time needs to be quite long for the new Rev C3 GPIO -> ETH PHY reset.

I received a number of new (SEEED STUDIO date 11/11/22) boards today and, unfortunately, 6500 is insufficient. I think we need to bump this to 10000. After doing so, they seem to boot successfully with ETH detected. Otherwise, I can actually see the ethernet device light up on boot, then when the GPIO asserts/deasserts it kills the PHY, extinguishing the green/amber LEDs, and results in the dreaded

[   33.864747] cpsw 4a100000.ethernet: phy "/ocp/interconnect@4a000000/segment@0/target-module@100000/ethernet@0/mdio@1000/ethernet-phy@0" not found on slave 0                          

This patch probably also needs to be fed upstream into the kernel as well.