power: qpnp-fg: increase FG error integration coefficient

Increase the fuel gauge error integration coefficient KI_COEFF_PRED_FULL
from 1.0 to 4.0 since it was found to give better battery level accuracy
than the default value.

CRs-Fixed: 768708
Change-Id: Ic3db0b534a0528e2ee33031f09a8fcc3ac4dfd2b
Signed-off-by: Xiaozhe Shi <xiaozhes@codeaurora.org>