migration/ram.c: start of migration_bitmap_sync_range is always 0

We can eliminate to pass 0.
Signed-off-by: NWei Yang <richardw.yang@linux.intel.com>
Message-Id: <20190430034412.12935-2-richardw.yang@linux.intel.com>
Reviewed-by: NDr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: NDr. David Alan Gilbert <dgilbert@redhat.com>

migration/ram.c

@@ -1681,10 +1681,10 @@ static inline bool migration_bitmap_clear_dirty(RAMState *rs,
 }
 
 static void migration_bitmap_sync_range(RAMState *rs, RAMBlock *rb,
-                                        ram_addr_t start, ram_addr_t length)
+                                        ram_addr_t length)
 {
     rs->migration_dirty_pages +=
-        cpu_physical_memory_sync_dirty_bitmap(rb, start, length,
+        cpu_physical_memory_sync_dirty_bitmap(rb, 0, length,
                                               &rs->num_dirty_pages_period);
 }
 
@@ -1773,7 +1773,7 @@ static void migration_bitmap_sync(RAMState *rs)
     qemu_mutex_lock(&rs->bitmap_mutex);
     rcu_read_lock();
     RAMBLOCK_FOREACH_NOT_IGNORED(block) {
-        migration_bitmap_sync_range(rs, block, 0, block->used_length);
+        migration_bitmap_sync_range(rs, block, block->used_length);
     }
     ram_counters.remaining = ram_bytes_remaining();
     rcu_read_unlock();
@@ -4196,7 +4196,7 @@ static void colo_flush_ram_cache(void)
     memory_global_dirty_log_sync();
     rcu_read_lock();
     RAMBLOCK_FOREACH_NOT_IGNORED(block) {
-        migration_bitmap_sync_range(ram_state, block, 0, block->used_length);
+        migration_bitmap_sync_range(ram_state, block, block->used_length);
     }
     rcu_read_unlock();