power: qpnp-fg: do not charge unknown hotswapped batteries

Currently, the fuel gauge driver has a bug where if an unknown battery
is hotswapped, the fuel gauge does not update the status, so it will be
considered disconnected still. This can cause the battery to still be
charged, and the SOC to be stuck at 100%.

Fix this by resetting the type back to "Unknown battery" after getting
an unknown battery hotswapped in.

Change-Id: Ib620fb5f7d1fa8f69f0c8b1418c447f43b576632
Signed-off-by: Xiaozhe Shi <xiaozhes@codeaurora.org>