Allow override default queue discipline

configname: CONFIG_NET_SCH_DEFAULT

Linux Kernel Configuration
└─>Networking support
└─>Networking options
└─>QoS and/or fair queueing
└─>Allow override default queue discipline
In linux kernel since version 4.2 (release Date: 2015-08-30)  
Support for selection of default queuing discipline.

Nearly all users can safely say no here, and the default
of pfifo_fast will be used. Many distributions already set
the default value via /proc/sys/net/core/default_qdisc.

If unsure, say N.