google_battery: add charging_state and charging_policy sysfs nodes

  - /sys/class/power_supply/battery/charging_state
  - /sys/class/power_supply/battery/charging_policy

Bug: 251427008
Change-Id: I3ca104a8dbc900762b853205a978edee232284e7
Signed-off-by: Jack Wu <[email protected]>
(cherry picked from commit 65b22ba388bb92d2c056d4651e03abdd7c3e0b38)
3 files changed