Fix some build issues (ARM toolchain).

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Olivier Martin <olivier.martin@arm.com>
Reviewed-by: Fu, Siyuan <siyuan.fu@intel.com>
Reviewed-by: Wu, Jiaxin <jiaxin.wu@intel.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@15533 6f19259b-4bc3-4df7-8a09-765794883524

NetworkPkg/TcpDxe/TcpDispatcher.c

@@ -304,12 +304,10 @@ TcpFlushPcb (
   )
 {
   SOCKET                    *Sock;
-  TCP_PROTO_DATA            *TcpProto;
 
   IpIoConfigIp (Tcb->IpInfo, NULL);
 
   Sock     = Tcb->Sk;
-  TcpProto = (TCP_PROTO_DATA *) Sock->ProtoReserved;
 
   if (SOCK_IS_CONFIGURED (Sock)) {
     RemoveEntryList (&Tcb->List);