[ax25-layer2] ECC vs. FCS

[Samuel A. Falvo II]

Don't forget the possibility of sending ECC packets upon retries too.
For example, if I send a 20-byte packet, but don't get an
acknowledgement before the timer expires, instead of resending the
whole 20 byte packet, I can try resending the 6-byte ECC for it.  Only
if that fails can we resort to resending the 20-byte packet + ECC.

-- 
Samuel A. Falvo II