[airos] remove channel brandwidth setter

as there is no support for setting the channel brandwidth

Author: edoput

netjsonconfig/backends/airos/converters.py

@@ -355,7 +355,6 @@ def to_intermediate(self):
             user_configs = {
                 'devname': r['name'],
                 'txpower': r.get('tx_power', 24),
-                'chanbw': r.get('channel_width', 0),
             }
             base.update(user_configs)
             radios.append(base)