power: qpnp-bms: reset coulomb counter upon PON

The coulomb counter is not being reset upon PON in PM8941 2.0.
Reset this manually in software until a hardware fix is applied.

Change-Id: I83efbc8433476ab7caadfc6684cf1c0e0294bd48
Signed-off-by: Xiaozhe Shi <xiaozhes@codeaurora.org>