The ethernet driver currently uses the legacy sw() macros. Add a
regmap to the driver that is derived from the parent mfd (like in
the mdio drivers). As a first consumer make use of that in the IRQ
functions.
Signed-off-by: Markus Stockhausen <markus.stockhausen@gmx.de>
Link: https://github.com/openwrt/openwrt/pull/22757
Signed-off-by: Robert Marko <robimarko@gmail.com>