power: qpnp-bms: add driver initialization

Add functions necessary for driver initialization and
exported CHARGE_FULL_DESIGN and CURRENT_NOW properties in the
bms power supply.

Update the Device tree files to include the new required property
"qcom,bms-batt-type".

IRQs are currently not set.

Change-Id: I4acaef987bf61350df68c70bb8de328338fc3fac
Signed-off-by: Xiaozhe Shi <xiaozhes@codeaurora.org>