mfd: twl-core: Add a clock subdevice for the TWL6032

Clock device needs no separate devicetree node, so add it as
a platform device. Other devices in the family also have controllable
clocks, but due to the lack of testing, just add it for the TWL6032
now.

Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
Link: https://lore.kernel.org/r/20230916100515.1650336-4-andreas@kemnade.info


Signed-off-by: Lee Jones <lee@kernel.org>