Remove misleading comment in TLS 1.3 key schedule code
The implementation documentation of
```
mbedtls_ssl_tls1_3_derive_early_secrets()
```
mentioned the PSK binder key, which is misleading because the
function doesn't actually calculate it.
Signed-off-by: Hanno Becker <hanno.becker@arm.com>
diff --git a/library/ssl_tls13_keys.c b/library/ssl_tls13_keys.c
index 78a5581..f1c8a12 100644
--- a/library/ssl_tls13_keys.c
+++ b/library/ssl_tls13_keys.c
@@ -368,9 +368,6 @@
* v
* PSK -> HKDF-Extract = Early Secret
* |
- * +-----> Derive-Secret(., "ext binder" | "res binder", "")
- * | = binder_key
- * |
* +-----> Derive-Secret(., "c e traffic", ClientHello)
* | = client_early_traffic_secret
* |