Fix sensorservice on integer sanitized builds.

Refactors unsigned integer overflows in cleanupImpl to fix integer
overflow sanitized builds.

Test: Compiled and checked output from sanitizer.
Bug: 30969751
Change-Id: I1c13b4b7b524d40b5732af8c36107cda9388c9ec
Merged-In: I1c13b4b7b524d40b5732af8c36107cda9388c9ec
1 file changed