[RFC] libertas: change quality calculation

[Holger Schurig]

> RSSI can be derived by adding Noise Floor to SNR value

I saw that, and it's actually like this coded. However, I was 
wondering if it is allowed to add "dBm" to "dB". Those are the 
documented units for "noisefloor" and "SNR", respectively.

See my question about this with the subject "Re: [RFC PATCH] 
mac80211: use hardware flags for signal/noise units".



Anyway, the reported quality from scan is similar (not identical) 
to the reported quality for iwconfig, so for my purpose it's 
good enought (BTW: it wasn't identical before my patches).