regulator: qpnp-lcdb: Fix LCDB boost voltage configuration

The newer version of LCDB uses a 25mV voltage step size for
boost, instead of 50mV. Identify the LCDB version and use the
appropriate step-size.

Change-Id: Ie79b3cc60e937d6ec15d29e599f1bc50a4c32958
Signed-off-by: Kiran Gunda <kgunda@codeaurora.org>