vga: Fix screen clear at end of Xen bootstrap.

Signed-off-by: Keir Fraser <keir.fraser@citrix.com>

xen/drivers/video/vga.c

@@ -111,12 +111,12 @@ void __init vga_endboot(void)
     switch ( vga_console_info.video_type )
     {
     case XEN_VGATYPE_TEXT_MODE_3:
-        vesa_endboot(vgacon_keep);
-        break;
-    case XEN_VGATYPE_VESA_LFB:
         if ( !vgacon_keep )
             memset(video, 0, columns * lines * 2);
         break;
+    case XEN_VGATYPE_VESA_LFB:
+        vesa_endboot(vgacon_keep);
+        break;
     default:
         BUG();
     }