reset: amlogic: convert driver to regmap

To allow using the same driver for the main reset controller and the
auxiliary ones embedded in the clock controllers, convert the
the Amlogic reset driver to regmap.

Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Link: https://lore.kernel.org/r/20240910-meson-rst-aux-v5-1-60be62635d3e@baylibre.com


Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>