add sanity check for full battery level (no 103%)

Based on these commits:
https://github.com/Quarx2k/android_frameworks_base/commit/e8d2b7a167738457066142adc9c7d1bfd09b6902
https://github.com/CyanogenMod/android_frameworks_base/commit/44c99a0910d2d7ff5a3f0c9631f9bddf0eabaeaf

This fixes disappearing battery icon and levels >100% when fully charged.
![screenshot_2013-09-06-14-27-50a](https://f.cloud.github.com/assets/2973420/1099372/6bb754ca-1735-11e3-8ced-0377e972ed72.png)