power: reset: qcom-pon: Rename variables to use generic naming

The qcom-pon driver was originally implemented for the PM8916 PMIC, and
as a result, several internal variable names still refer to 'pm8916'.
However, the driver has since been extended to support other PMICs as
well.

This patch renames those variables to use more generic and consistent
names, improving clarity and reducing confusion for non-PM8916 devices.

Signed-off-by: Taeyoung Kwon <Taeyoung.Kwon@telit.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20250521131116.2664-1-Taeyoung.Kwon@telit.com


Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>