regulator: fan53555: add support for die revision 23 chips

The chips with die revision 23 have 600 mV minimum voltage and 12.5 mV
step size. Add support for chips with this die revision.

Change-Id: Ie63637bdcfae73a706f364e74908d285c2a60954
Signed-off-by: Fenglin Wu <fenglinw@codeaurora.org>