The block returned from Mtftp6RemoveBlockNum is not the total received and
saved block number if it works in passive (Slave) mode.
The issue was exposed by the EMS test.
Cc: Ye Ting <ting.ye@intel.com>
Cc: Fu Siyuan <siyuan.fu@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Wu Jiaxin <jiaxin.wu@intel.com>
Reviewed-by: Ye Ting <ting.ye@intel.com>