urtwn: add driver for USB Wifi sticks using RTLS8188CU/RTLS8192CU chips
I use this driver for some time successfully and it supports still available USB Wifi sticks.
The urtwn driver is originally from http://freenicdrivers.la.coocan.jp.
But since some changes in the illumos USB interface recompiling was necessary. To prevent such problems in the future I would prefer to have this driver in illumos-gate.
It is BSD 2 simple clause licensed and I got the permission from Masayuki Murayama to push the driver to Illumos.