Update X25519+Kyber ID.

This updated value is not in the private use area and can hopefully be
more stable over time.

Change-Id: Ieda34ec0f356cfd03365973f611a6edc23431e29
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/58525
Commit-Queue: Adam Langley <agl@google.com>
Reviewed-by: David Benjamin <davidben@google.com>
diff --git a/include/openssl/ssl.h b/include/openssl/ssl.h
index b5bec5c..a3b6a86 100644
--- a/include/openssl/ssl.h
+++ b/include/openssl/ssl.h
@@ -2335,7 +2335,7 @@
 #define SSL_CURVE_SECP521R1 25
 #define SSL_CURVE_X25519 29
 #define SSL_CURVE_CECPQ2 16696
-#define SSL_CURVE_X25519KYBER768 0xfe31
+#define SSL_CURVE_X25519KYBER768 0x6399
 #define SSL_CURVE_P256KYBER768 0xfe32
 
 // SSL_get_curve_id returns the ID of the curve used by |ssl|'s most recently