Revert "Revert "libsuspend: move to exponential backoff""

Test: Left device overnight, libsuspend exponential backoff
path was exercised multiple time and device went into suspend.

This reverts commit 23c8bab0243bc6e7be8b95702c262c354009d56a.

Change-Id: Ifa5c41bc1ca5da7baa28b216d70305c98806bf36
1 file changed