PerformanceControl: Fix a possible NPE

In case of DRAWER_MODE set to 3, if we select advanced settings from
drawer, it increases the item position by 1 rather than 2. As a result,
itemId points to VoltageControl fragment instead of Advanced fragment.

Change-Id: I595246e681d70080bb8c82a25e5f31dd0243da6a
Merge branch 'android-4.4' of https://github.com/omnirom/android_packages_apps_PerformanceControl into kk4.4