power: qpnp-fg: load the same batt temp after a restart

Currently, when the software rbias feature is enabled, the battery
temperature remains at 25 degrees C for a long time after a fuel gauge
restart. This is because until the next software temperature update
occurs, the default battery temperature in the fuel gauge will be
25 degrees C.

Fix this by writing in the old battery temperature after a restart if
the software rbias control is enabled.

CRs-Fixed: 867716
Change-Id: I6f5f2b125ae53c3ca89b5d4a67890b689e4d74ab
Signed-off-by: Xiaozhe Shi <xiaozhes@codeaurora.org>