regulator: qpnp-lcdb: Add n_voltages property for LCDB regulators

Define n_voltages property for LDO and NCP regulators as some
clients require it to be defined for setting voltage on the
regulators.

Change-Id: Id47644a585a9bc95713909e7535cb1347c828f02
Signed-off-by: Jishnu Prakash <jprakash@codeaurora.org>