charger: Display battery percentage on the charging screen

Let user know the exact battery percentage under power off
charging.

Change-Id: Ie2abaeee0e443cd2a730780488287ad4d9ea1e9a
 healthd: increase healthd fast timer to 10mins instead of 1min

healthd 1 min wakeups are causing significant power impact
during static display use case. so increasing the timer to 10min.

Change-Id: If7a514e4152789144242e198175918b6687c3bcf