Solely use raw X.509 name data references including SEQUENCE header

So far, the CRT frame structure `mbedtls_x509_crt_frame` used
as `issuer_raw` and `subject_raw` the _content_ of the ASN.1
name structure for issuer resp. subject. This was in contrast
to the fields `issuer_raw` and `subject_raw` from the legacy
`mbedtls_x509_crt` structure, and caused some information
duplication by having both variants `xxx_no_hdr` and `xxx_with_hdr`
in `mbedtls_x509_crt` and `mbedtls_x509_crt_frame`.

This commit removes this mismatch by solely using the legacy
form of `issuer_raw` and `subject_raw`, i.e. those _including_
the ASN.1 name header.
diff --git a/include/mbedtls/x509.h b/include/mbedtls/x509.h
index 2a9ce99..e37573f 100644
--- a/include/mbedtls/x509.h
+++ b/include/mbedtls/x509.h
@@ -313,8 +313,8 @@
  * Internal module functions. You probably do not want to use these unless you
  * know you do.
  */
-int mbedtls_x509_get_name( unsigned char **p, const unsigned char *end,
-                   mbedtls_x509_name *cur );
+int mbedtls_x509_get_name( unsigned char *p, size_t len,
+                           mbedtls_x509_name *cur );
 int mbedtls_x509_get_alg_null( unsigned char **p, const unsigned char *end,
                        mbedtls_x509_buf *alg );
 int mbedtls_x509_get_alg( unsigned char **p, const unsigned char *end,