add default virtcon initialization

When going through the default devices, we don't initialize the virtio
console, unless we're doing -nographic.

I suppose that's just a leftover from the recent code restructuring, so
let's put it in.

Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
(cherry picked from commit 38536da1e3)

vl.c

@@ -5712,6 +5712,8 @@ int main(int argc, char **argv, char **envp)
             add_device_config(DEV_PARALLEL, "vc:80Cx24C");
         if (default_monitor)
             monitor_parse("vc:80Cx24C", "readline");
+        if (default_virtcon)
+            add_device_config(DEV_VIRTCON, "vc:80Cx24C");
     }
     if (default_vga)
         vga_interface_type = VGA_CIRRUS;