generic: platform/mikrotik: add NVMEM layout driver
Currently, information from MikroTik hard_config is only available via
sysfs, meaning that we have to rely on userspace to for example setup MACs.
So, lets provide a basic NVMEM layout based driver to expose the same cells
as sysfs driver exposes.
Do note that the we dont extract the WLAN caldata and BDF-s at this point.
Reviewed-by: Thibaut VARĂˆNE <hacks@slashdirt.org>
Link: https://github.com/openwrt/openwrt/pull/15665
Signed-off-by: Robert Marko <robimarko@gmail.com>