Port rue(4) from FreeBSD:

Port rue(4) from FreeBSD:
dev/usb/if_rue.c	rev 1.14, 1.20
dev/usb/if_ruereg.h	rev 1.3
dev/mii/ruephy.c	rev 1.1.4.1
dev/mii/ruephyreg.h	rev 1.1.4.1
modules/rue/Makefile	rev 1.2

This driver supports:
RealTek RTL8150 based USB ethernet devices
- Melco LUA-KTX
- GREEN HOUSE GH-USB100B
- Billionton ThumbLAN USBKR2-100B

Changes to FreeBSD version:
- use hw.rue as sysctl node instead of hw.usb.rue
- cleanup rue_attach() code path
- RUE_{LOCK, UNLOCK}() ==> crit_{enter, exit}()
- get rid of qdat
- nuke rue_softc.{rue_info, rue_unit}
- use callout_*()
- use m_getcl() instead of MGETHDR() and MCLGET()

Thanks Shunsuke Akiyama <akiyama@FreeBSD.org> and others for rue(4)

Lack of rue(4) in our base was first noticed by swilder,
thanks him for his reminding

Approved-by: dillon
Tested-by: me (with a Billionton ThumbLAN USBKR2-100B)