package/opensc: fix build with libressl

Fix the following build failure with libressl raised since the addition
of the package in commit 8aaa7ecb:

In file included from internal.h:45,
                 from card-authentic.c:32:
/nvmedata/autobuild/instance-29/output-1/host/powerpc64-buildroot-linux-gnu/sysroot/usr/include/openssl/x509v3.h:802:10: error: expected ')' before '*' token
  802 | uint32_t X509_get_extension_flags(X509 *x);
      |          ^~~~~~~~~~~~~~~~~~~~~~~~

Fixes:
 - http://autobuild.buildroot.org/results/7b50ab363c174636fb27d554223287d7496676ed



Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Arnout Vandecappelle <arnout@mind.be>