surfaceflinger: Add all display connections to connection list.

1. Revert "surfaceflinger: Remove deadlock condition."
   This reverts commit 3924ab90a956b15610f45e229e051756c94ba1b8.
2. Add all display event connections to connection list to avoid
   deadlock condition.

Conflicts:

	services/surfaceflinger/EventThread.cpp

Change-Id: Ia65e217a5130572d0724d3c4fd9f2e962c0ffb50
(cherry picked from commit 5aec1edc1f4fa0562d379b5c85a1c9de943b7087)
CRs-Fixed: 421346