Move input event list initialisation and storage from DDX to DIX.

Rather than letting the DDX allocate the events, allocate them once in the DIX
and just pass it around when needed.

DDX should call GetEventList() to obtain this list and then pass it into
Get{Pointer|Keyboard}Events.

dix/events.c

@@ -5711,6 +5711,10 @@ InitEvents(void)
 	DontPropagateMasks[i] = 0;
 	DontPropagateRefCnts[i] = 0;
     }
+
+    InputEventList = InitEventList(GetMaximumEventsNum());
+    if (!InputEventList)
+        FatalError("[dix] Failed to allocate input event list.\n");
 }
 
 /**