Backporting Intel PRO/Wireless 6205a FreeBSD 9.0 modules to 8.2

My old professionnal Dell Latitude D630 laptop was replaced by a new Dell Latitude E5420… and this new one have a wireless chipset not supported on FreeBSD 8.2:

[root@laptop]~#dmesg | grep iwn
iwn0: <Intel(R) PRO/Wireless 6205a> mem 0xe5300000-0xe5301fff irq 17 at device 0.0 on pci2
0xe5300000-0xe5301fff irq 17 at device 0.0 on pci2
iwn0: MIMO 2T2R, MoW, address a0:88:b4:7d:40:9c
iwn0: [ITHREAD]
iwn0: 11a rates: 6Mbps 9Mbps 12Mbps 18Mbps 24Mbps 36Mbps 48Mbps 54Mbps
iwn0: 11b rates: 1Mbps 2Mbps 5.5Mbps 11Mbps
iwn0: 11g rates: 1Mbps 2Mbps 5.5Mbps 11Mbps 6Mbps 9Mbps 12Mbps 18Mbps 24Mbps 36Mbps 48Mbps 54Mbps
iwn6005fw: could not load firmware image, error 2
iwn0: iwn_read_firmware: could not load firmare image "iwn6005fw"
iwn0: iwn_init_locked: could not read firmware, error 22

But, this new chipset is supported on FreeBSD-current, then I've backported it to 8.2.
I had to do 3 small changes in if_iwn.c file : One function name to revert (pci_find_cap to pci_find_extcap), and remove 2 lines (use of ic_rxstream and ic_txstream).
You can install this drivers like this:

cd /tmp

fetch http://gugus69.free.fr/tools/FreeBSD-8.2-iwn-current.tgz

cd /

tar zxvf /tmp/FreeBSD-8.2-iwn-current.tgz

cd /usr/src

make buildkernel

make installkernel

reboot

I've tested Internet browsing and small files transfert with this drivers without problem.