wpa_supplicant seems to prefer 2.4GHz over 5GHz

[John Frankish]

> > Also posted this in  https://bugzilla.kernel.org/show_bug.cgi?id=175401.
> > 
> According to the wpa_supplicant AP scoring, it would indeed seem that the 2.4GHz AP
> is proffered since it has better SNR (although the SNR for both is good. Generally,
> wpa_s considers any SNR above 30 as good).
> 
> a0:55:4f:66:d5:18 freq=2447 qual=0 noise=-89~ level=-49 snr=40* flags=0xb age=0 est=65000
> a0:55:4f:66:d5:10 freq=5240 qual=0 noise=-92~ level=-67 snr=25 flags=0xb age=0 est=390001
> 
> perhaps the scoring can be tweaked to more aggressively favor 5.2 in case of close good SNR. 
> 
The fact that I get four times the throughput (as per iperf) without changing anything except the frequency would seem to indicate that the wpa_supplicant algorithm could use some adjustment?