regulators: Added ab8500 v2 support

The AUX3 regulator voltage setting is changed in ab8500 v2 compared
to ab8500 v1. This patch adds v2 support while keeping support for
v1.

Signed-off-by: Bengt Jonsson <bengt.g.jonsson@stericsson.com>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>