hwc: external: Cleanup overlay objects on external disconnect.

Cleanup overlay objects and close fds when external is disconnected.  Without
this, the external does not come on when cable connected-disconnected multiple
times when device is in suspended state.

Bug: 7150885 (part of the fix)
Bug: 7295979
Bug: 7150885 (partial)
Change-Id: I1ae2ce7220b9928dde332ce3644dbe671d25c7e6
Signed-off-by: Iliyan Malchev <malchev@google.com>
3 files changed