power: qpnp-fg: fix full soc esr workaround constant

In the previous change:

power: qpnp-fg: Support configuring battery soc via charge_full property
408a908b

a work around was introduced to set the fuel gauge system battery SOC to
0x7FDF3B (50%) whenever full was reached. This is incorrect and can cause
SOC inaccuracies at near end of charge.

The correct value should be 0xFFF971 (99.9%). Fix this in the fuel gauge
driver.

Change-Id: I55c3348a3cb118bd5868602829f9924ae1be2f13
Signed-off-by: Xiaozhe Shi <xiaozhes@codeaurora.org>