regulator: anatop: Remove unneeded fields from struct anatop_regulator

These fields are only used in anatop_regulator_probe() so use local
variables instead. The *initdata is not used so can be removed.
The *anatop is renamed to *regmap for better readability.
Use u32 instead of int for the variables used as third argument of
of_property_read_u32().

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Mark Brown <broonie@kernel.org>