Removing BatteryStatsImpl lock that causes a deadlock

Please see the original change I0d6b4a7b12b234939cb6eb3a32658b28f61dff4f,
where the additional locks were first introduced, but the original lock
was not consistently removed.

Bug: 153826721
Bug: 153813215
Test: Disable and reenable WiFi.

Change-Id: I0e68889e9dfe22495d64b16a495a83434b816304