console: displaystate init revamp

We have only one DisplayState, so there is no need for the "next"
linking, rip it.  Also consolidate all displaystate initialization
into init_displaystate().  This function is called by vl.c after
creating the devices (and thus all QemuConsoles) and before
initializing DisplayChangeListensers (aka gtk/sdl/vnc/spice ui).

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
diff --git a/vl.c b/vl.c
index 0598998..63fe9a4 100644
--- a/vl.c
+++ b/vl.c
@@ -4331,8 +4331,7 @@
 
     net_check_clients();
 
-    /* just use the first displaystate for the moment */
-    ds = get_displaystate();
+    ds = init_displaystate();
 
     /* init local displays */
     switch (display_type) {
@@ -4388,9 +4387,6 @@
     }
 #endif
 
-    /* display setup */
-    text_consoles_set_display(ds);
-
     if (foreach_device_config(DEV_GDB, gdbserver_start) < 0) {
         exit(1);
     }