Fix channel frequency/flags in radiotap structures.
Now I can see probes cycling 1->14 instead of just
sitting at channel 1.

Add a few RT73 devices that are known to exist in the wild.

prefix debug messages with the device name

- add rum(4), a driver for the next generation Ralink Technology USB 802.11a/b/g
wireless network devices.

not yet fully functional, putting it in the tree so others can hack on it too.