x509: trailing bytes in DER: fix bug

Fix bug in mbedtls_x509_crt_parse that caused trailing extra data in the
buffer after DER certificates to be included in the raw representation. #377
diff --git a/ChangeLog b/ChangeLog
index 56b712d..017d6a2 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -7,6 +7,8 @@
      arguments where the same (in-place doubling). Found and fixed by Janos
      Follath. #309
    * Fix issue in Makefile that prevented building using armar. #386
+   * Fix bug in mbedtls_x509_crt_parse that caused trailing extra data in the
+     buffer after DER certificates to be included in the raw representation.
 
 Changes
    * On ARM platforms, when compiling with -O0 with GCC, Clang or armcc5,