Add MBEDTLS_PRIVATE wrapping to sample programs.

Signed-off-by: Mateusz Starzyk <mateusz.starzyk@mobica.com>
diff --git a/programs/x509/cert_app.c b/programs/x509/cert_app.c
index fb24843..2adef39 100644
--- a/programs/x509/cert_app.c
+++ b/programs/x509/cert_app.c
@@ -335,7 +335,7 @@
 
             mbedtls_printf( "%s\n", buf );
 
-            cur = cur->next;
+            cur = cur->MBEDTLS_PRIVATE(next);
         }
 
         /*
diff --git a/programs/x509/cert_write.c b/programs/x509/cert_write.c
index 18174d8..ff7cf98 100644
--- a/programs/x509/cert_write.c
+++ b/programs/x509/cert_write.c
@@ -518,7 +518,7 @@
         }
 
         ret = mbedtls_x509_dn_gets( issuer_name, sizeof(issuer_name),
-                                 &issuer_crt.subject );
+                                 &issuer_crt.MBEDTLS_PRIVATE(subject) );
         if( ret < 0 )
         {
             mbedtls_strerror( ret, buf, 1024 );
@@ -552,7 +552,7 @@
         }
 
         ret = mbedtls_x509_dn_gets( subject_name, sizeof(subject_name),
-                                 &csr.subject );
+                                 &csr.MBEDTLS_PRIVATE(subject) );
         if( ret < 0 )
         {
             mbedtls_strerror( ret, buf, 1024 );
@@ -562,7 +562,7 @@
         }
 
         opt.subject_name = subject_name;
-        subject_key = &csr.pk;
+        subject_key = &csr.MBEDTLS_PRIVATE(pk);
 
         mbedtls_printf( " ok\n" );
     }
@@ -606,7 +606,7 @@
     //
     if( strlen( opt.issuer_crt ) )
     {
-        if( mbedtls_pk_check_pair( &issuer_crt.pk, issuer_key ) != 0 )
+        if( mbedtls_pk_check_pair( &issuer_crt.MBEDTLS_PRIVATE(pk), issuer_key ) != 0 )
         {
             mbedtls_printf( " failed\n  !  issuer_key does not match "
                             "issuer certificate\n\n" );