Main part is copied from ar71xx original driver rb91x_nand
written by Gabor Juhos <juhosg@openwrt.org>.
What is done:
* Support of kernel 5.4 and 5.10,
* DTS support,
* New gpio API (gpiod_*) support.
Reviewed-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
Signed-off-by: Denis Kalashnikov <denis281089@gmail.com>