Remove unnecessary addition to buffer size estimation

Signed-off-by: Andrzej Kurek <andrzej.kurek@arm.com>
diff --git a/library/x509write_crt.c b/library/x509write_crt.c
index ea8471c..274eb4b 100644
--- a/library/x509write_crt.c
+++ b/library/x509write_crt.c
@@ -201,7 +201,6 @@
                     CHECK_OVERFLOW_ADD(buflen, chunk->val.len);
                     chunk = chunk->next;
                 }
-                CHECK_OVERFLOW_ADD(buflen, cur->node.san.unstructured_name.len);
                 CHECK_OVERFLOW_ADD(buflen, 4 + 1);
                 break;
             }