dtbocfg: Allow users to load devicetree overlays from userspace

[Jonathan Bennett]

> With the addition of many dev-focused and expandable devices recently
> such as OpenWrt One, the Banana Pi R4 series, etc; it would be
> extremely useful and beneficial to allow users to load device tree
> overlays to enable additional hardware support (E.g. MikroBus cards,
> Hats, etc).
>
> I have submitted a kmod package that addresses this issue in a similar
> manner to the current Raspberry Pi targets, using a configfs mount.
> https://github.com/ikwzm/dtbocfg
>
> PR: https://github.com/openwrt/packages/pull/26832
>
> I have also created a proof-of-concept package showing how `dtbocfg`
> may be consumed by other OpenWrt packages.
> https://github.com/vidplace7/openwrt-dtbo/tree/main/openwrt-one-mikrobus-spidev
Wanted to add that I've successfully built these packages for my OpenWRT 
One, giving me access to a LoRa MikroBus card over SPI. Was then able to 
install and run Meshtasticd to interact with that LoRa radio as a 
result. It would be outstanding if this could be supported without 
requiring local OpenWRT compilation for each user.
>
> I welcome critique on this submission, and look forward to moving this
> issue forward.
>
For what it's worth,

Acked-by: Jonathan Bennett <jbennett at incomsystems.biz>