regulator: qpnp-lcdb: Add support for some LCDB DT properties

Add support for the following LCDB devicee tree properties:
"qcom,high-p2-blank-time-ns" to control the higher clamp threshold for
p2 minimum on time.
"qcom,low-p2-blank-time-ns" to control the lower clamp threshold for
p2 minimum on time.
"qcom,mpc-current-thr-ma" to control the mpc threshold for inductor
current after start up is done.

Change-Id: Iabe2cc2c9913f433dd55d952a267f94ce0682f0e
Signed-off-by: Jishnu Prakash <jprakash@codeaurora.org>