ram: save_live_setup() we don't need to synchronize the dirty bitmap.

1st: we were synchonizing the dirty bitmap before calling
      memory_global_dirty_log_start().

2nd: We are marking all pages as dirty anywhere, no reason to go
     through all the bitmap to "mark" dirty same pages twice.

So, call removed.

Signed-off-by: Juan Quintela <quintela@redhat.com>

arch_init.c

@@ -308,8 +308,6 @@ static int ram_save_setup(QEMUFile *f, void *opaque)
     ram_addr_t addr;
     RAMBlock *block;
 
-    memory_global_sync_dirty_bitmap(get_system_memory());
-
     bytes_transferred = 0;
     last_block = NULL;
     last_offset = 0;