power: qpnp-linear-charger: update chg_done flag timely

Chg_done flag should be updated timely after battery capacity
drops below 100%, or else if charging not enabled, will show
battery FULL even if capacity less than 100%.

CRs-Fixed: 650740
Change-Id: I85b9125ece5cf56bcc534898ddcb30304ae2fe64
Signed-off-by: Zhenhua Huang <zhenhuah@codeaurora.org>