igb update for testing

[Thomas Nikolajsen]

>Please test the following patch:
>https://leaf.dragonflybsd.org/~sephe/igb-2.5.3.diff
>
>If any tests with i210 or i211 is highly appreciated.
i210 works fine here with your patch applied to master.

My test was buildkernel from host w/ i210 using i210 for NFS for /usr/src & /usr/obj:
build time was same as w/o patch; resulting kernel works.

Host is a PC Engines apu2b4, http://pcengines.ch/apu2b4.htm, which works great w/ DragonFly.

 -thomas

- dmesg
igb0: <Intel(R) PRO/1000 I210_COPPER_FLASHLESS> port 0x1000-0x101f mem 0xfe62000
0-0xfe623fff,0xfe600000-0xfe61ffff at device 0.0 on pci1
igb0: MAC address: 00:0d:b9:41:de:2c

- pciconf -lv
igb0 at pci0:1:0:0:        class=0x020000 card=0x00008086 chip=0x157b8086 rev=0x03 hdr=0x00
    vendor     = 'Intel Corporation'
    device     = 'I210 Gigabit Network Connection'
    class      = network
    subclass   = ethernet