power: android-battery: use freezable workqueue for monitor

Alarmtimer may execute the monitor early in the resume sequence.  Freeze the
monitor while suspended, and unfreeze after the battery charger and fuel gauge,
etc. drivers are resumed.

Change-Id: Iefda1c642d4b2440169d90d2bee2888fc70e030a
Signed-off-by: Todd Poynor <toddpoynor@google.com>