ARM: dts: msm: Add configurability support to pm6150 charger/qg

Currently, pm6150 charger and qgauge optional configurations are
defined within primary dt file which prevent its configurations
from being over written from the device specific overlay files
like sm6150 qrd or idp dtsi files.

Fix this by migrating configurable parameters to device specific
overlay files for sm6150 and sdmmagpie target.

Change-Id: I002f060fba120213928af9ae490a9e9494bb7e68
Signed-off-by: Umang Agrawal <uagrawal@codeaurora.org>