Add support for WEP (encryption) for silver and gold WaveLAN/IEEE turbo cards.

Add support for WEP (encryption) for silver and gold WaveLAN/IEEE turbo cards.
Also update wicontrol to enable/disable encryption, set WEP keys and set the
TX key index. Silver cards only have 40-bit keys. This is something of a quick
hack, but it works well enough for me to commit this from the LinuxWorld
exhibit floor.

The WEP support only shows up if you have a card that supports it.

Would have been approved by: jkh, if he hadn't wandered off somewhere
Approved in his place by: msmith, who's standing right here