reset: amlogic: split the device core and platform probe

To prepare the addition of the auxiliary device support, split
out the device coomon functions from the probe of the platform device.

The device core function will be common to both the platform and auxiliary
driver.

Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Link: https://lore.kernel.org/r/20240910-meson-rst-aux-v5-8-60be62635d3e@baylibre.com


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