power: qpnp-fg: set patch negative current bit

There’s a bit in the fuel gauge that need to be enabled so that the FG
only reads negative currents when the charger is charging the battery.

This is needed to make sure that in low current situation the fuel gauge
monotonic SoC does not get stuck due to incorrect offsets reading negative
currents.

CRs-Fixed: 768033
Change-Id: I612408ab0b301f07197434aa4c95d470aa345c88
Signed-off-by: Xiaozhe Shi <xiaozhes@codeaurora.org>