AudioFlinger: revert adjust standby delay on VOIP RX output

This reverts the fix for b/227811055.

If VoIP client starts/stops the track quickly, it might cause
the VoIP output standby/resume frequently.

Bug: 285443585
Test: 1. made VoIP call and confirmed the VoIP output didn't standby
         frequently.
      2. played music and made voice-call, music resumed on speaker
         when the call ends.
      3. played youtube music and received an incoming call, confirmed
         the music resumed from speaker when the incoming call ended.
Change-Id: I37b8b82cc46f4088dd1cf02ef6ddcda721504257
Signed-off-by: Carter Hsu <carterhsu@google.com>