[FS#81] Add ability to limit wifi channels for "auto" channel selection mode

[LEDE Bugs]

A new Flyspray task has been opened.  Details are below. 

User who did this - Jon Grossart (jon.grossart) 

Attached to Project - LEDE Project
Summary - Add ability to limit wifi channels for "auto" channel selection mode
Task Type - Feature Request
Category - Base system
Status - Unconfirmed
Assigned To - 
Operating System - All
Severity - Low
Priority - Very Low
Reported Version - Trunk
Due in Version - Undecided
Due Date - Undecided
Details - A nice feature for LEDE would be ability to limit what channels are used for when setting an interface up for "auto" channel selection.

For example, on 2.4 GHz, while channels 1-11 are often available, it's better to just use 1, 6, and 11. But for "auto" mode, the router will still sometimes pick one of the in between channels. If there was some sort of checklist where you could pick only those channels you want the algorithm to use, it would allow finer grained control over the process.

It would be trickier for the GHz band though, since there are often different power limits associated with the different bands.

More information can be found at the following URL:
https://bugs.lede-project.org/index.php?do=details&task_id=81