ure: lock MII bus operations

[rkitover_gmail.com]

Summary

A race condition in the MII layer causes spurious events, see:

https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=252165

. Use a lock to serialize access to MII operations and drop ticks when
MII is locked.

Signed-off-by: Rafael Kitover <[e-mail]>

[rkitover_gmail.com]

Add Differential Revision

[pouria]

I'd be happy to review this, but I need reproduction steps.

[sanpei]

Hi @pouria.

I can reproduce below steps

Device: Raspberry Pi Zero 2W(arm64)
OS: 15.0-RELEASE + (D55682) (maybe also -current)
Setup : CARP configured on the ure interface.
Dongle: Lenovo USB-C to LAN

Steps:
Machine A (Remote): Run ping [Unassigned Local IP].
Machine B (Target): Run the route -n monitor command in four separate instances and more.

Result: NG (Failed)

and this change is fixed(I'm still testing some devices. After finish, I will report it)

[rkitover_gmail.com]

Does anyone know how I can get an adapter or hub device with the C variant chip (latest revision?)

[rkitover_gmail.com]

Fix style based on zlei's review