* When build a DHCP message in function DhcpSendMessage() or DhcpRetransmit(), a new NET_BUF is created by the library of NetbufFromExt, but it's not freed after it is sent out. This patch is to fix this memory leak issue. V2: * Since packet has already been referred by DhcpSb->LastPacket, and will be freed when sending another packet or clean up, there is no need to add an extra free function in NetbufFromExt. Cc: Jiaxin Wu <jiaxin.wu@intel.com> Cc: Ye Ting <ting.ye@intel.com> Cc: Fu Siyuan <siyuan.fu@intel.com> Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Wang Fan <fan.wang@intel.com> Reviewed-by: Jiaxin Wu <jiaxin.wu@intel.com> Reviewed-by: Fu Siyuan <siyuan.fu@intel.com>