power: android-battery: Add USB and AC battery power supplies

For reflecting board-level decisions on whether USB or AC charger
is connected, which may differ from charger power supply notion
of USB input path (which may be connected to an AC charger) vs.
AC input path.

Change-Id: I9d2eb446db8b4d9496ba7ce1472d0e7a4d4e24ef
[toddpoynor@google.com: refactoring]
Signed-off-by: hongmin.son <hongmin.son@samsung.com>
Signed-off-by: Todd Poynor <toddpoynor@google.com>