Remove MBEDTLS_OID_X509_EXT_xxx constants

They're just aliases for the corresponding MBEDTLS_X509_EXT_xxx. We don't
need separate names.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/library/x509_crt.c b/library/x509_crt.c
index 5528763..0b0e8d1 100644
--- a/library/x509_crt.c
+++ b/library/x509_crt.c
@@ -1015,7 +1015,7 @@
                 }
                 break;
 
-            case MBEDTLS_OID_X509_EXT_CERTIFICATE_POLICIES:
+            case MBEDTLS_X509_EXT_CERTIFICATE_POLICIES:
                 /* Parse certificate policies type */
                 if ((ret = x509_get_certificate_policies(p, end_ext_octet,
                                                          &crt->certificate_policies)) != 0) {
@@ -1866,7 +1866,7 @@
         }
     }
 
-    if (crt->ext_types & MBEDTLS_OID_X509_EXT_CERTIFICATE_POLICIES) {
+    if (crt->ext_types & MBEDTLS_X509_EXT_CERTIFICATE_POLICIES) {
         ret = mbedtls_snprintf(p, n, "\n%scertificate policies : ", prefix);
         MBEDTLS_X509_SAFE_SNPRINTF;