smb-lib: report not charging when battery is missing

When the battery is missing from the device the battery power supply
will still report that it is charging. Fix this by reporting the charge
status as "not charging" when the battery is missing.

Change-Id: I1150ccaa722109f3ea6a4a10e026709d3686e28b
Signed-off-by: Nicholas Troast <ntroast@codeaurora.org>