composer: Reset pending power modes on destruction of display

- When secure session going on, if external is destroyed
  pending power state is not reset.
- On next external connect, power on rejected (sent from SF)
  due to pending power state.
- Ideally, better to reset on destruction of display.
- stability use case: secure display + hpd (~1 hr)

CRs-Fixed: 2582345
Change-Id: I95f9fcd2f6ebd47f09d35c32a300778341a93eee
1 file changed