soc: mediatek: PMIC wrap: don't duplicate the wrapper data

As we add support for more devices struct pmic_wrapper_type will grow and
we do not really want to start duplicating all the elements in
struct pmic_wrapper.

Signed-off-by: John Crispin <blogic@openwrt.org>
Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>