codec2: add smoothfactor when checking n-th work

pipeline watcher's queued work counter included smoothfactor, if we
don't add it in elapsed(), it is easy to cause CCodec queue call timeout

CRs-Fixed: 2984012
Test: Verified on OnePlus 9 that YouTube video does
      not unpause itself.
Change-Id: Ia2dbf3a7cf0da4805398cf44780ad3dacbaf1a1b