power:qpnp-charger:when charger out,wait for a moment to enable soc change

when usb charger in ,do not allow capacity decrease. This may cause unplugin charger, the soc will decrease immediately,
such as from 100% to 99%. So when charger out, wait for a moment to enable soc change

Change-Id: I5e614027c4909b7c98b3359b8dc432f909f665ea
Signed-off-by: libing <l00228880@notesmail.huawei.com>