Use cipher_info accessor functions in TLS code

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/library/ssl_ticket.c b/library/ssl_ticket.c
index bce9a1c..db2bb52 100644
--- a/library/ssl_ticket.c
+++ b/library/ssl_ticket.c
@@ -141,13 +141,13 @@
     if( cipher_info == NULL )
         return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
 
-    if( cipher_info->mode != MBEDTLS_MODE_GCM &&
-        cipher_info->mode != MBEDTLS_MODE_CCM )
+    if( mbedtls_cipher_info_get_mode( cipher_info ) != MBEDTLS_MODE_GCM &&
+        mbedtls_cipher_info_get_mode( cipher_info ) != MBEDTLS_MODE_CCM )
     {
         return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
     }
 
-    if( cipher_info->key_bitlen > 8 * MAX_KEY_BYTES )
+    if( mbedtls_cipher_info_get_key_bitlen( cipher_info ) > 8 * MAX_KEY_BYTES )
         return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
 
 #if defined(MBEDTLS_USE_PSA_CRYPTO)