NetworkPkg: Fixes to static code analysis hits

Introducing fixes to memory leak issues identified by static code analysis
tool.

Cc: Jiaxin Wu <jiaxin.wu@intel.com>
Cc: Siyuan Fu <siyuan.fu@intel.com>
Signed-off-by: Maciej Rabeda <maciej.rabeda@linux.intel.com>
Reviewed-by: Philippe Mathieu-Daude <philmd@redhat.com>
Reviewed-by: Siyuan Fu <siyuan.fu@intel.com>
Reviewed-by: Jiaxin Wu <jiaxin.wu@intel.com>

NetworkPkg/TcpDxe/TcpDispatcher.c

@@ -390,6 +390,7 @@ TcpAttachPcb (
                   );
   if (EFI_ERROR (Status)) {
     IpIoRemoveIp (IpIo, Tcb->IpInfo);
+    FreePool (Tcb);
     return Status;
   }