package/libiec61850: fix CVE-2020-15158

package/libiec61850: fix CVE-2020-15158

In libIEC61850 before version 1.4.3, when a message with COTP message
length field with value < 4 is received an integer underflow will happen
leading to heap buffer overflow. This can cause an application crash or
on some platforms even the execution of remote code. If your application
is used in open networks or there are untrusted nodes in the network it
is highly recommend to apply the patch. This was patched with commit
033ab5b. Users of version 1.4.x should upgrade to version 1.4.3 when
available. As a workaround changes of commit 033ab5b can be applied to
older versions.

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>