Update based on comments

Signed-off-by: Xiaofei Bai <xiaofei.bai@arm.com>
diff --git a/library/ssl_misc.h b/library/ssl_misc.h
index e1c69a8..a94c79f 100644
--- a/library/ssl_misc.h
+++ b/library/ssl_misc.h
@@ -529,7 +529,7 @@
      * Handshake specific crypto variables
      */
 #if defined(MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL)
-    int tls1_3_kex_modes; /*!< key exchange modes for TLS 1.3 */
+    int tls13_kex_modes; /*!< key exchange modes for TLS 1.3 */
 #endif /* MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL */
 
 #if !defined(MBEDTLS_DEPRECATED_REMOVED)
@@ -765,7 +765,7 @@
         unsigned char early    [MBEDTLS_TLS1_3_MD_MAX_SIZE];
         unsigned char handshake[MBEDTLS_TLS1_3_MD_MAX_SIZE];
         unsigned char app      [MBEDTLS_TLS1_3_MD_MAX_SIZE];
-    } tls1_3_master_secrets;
+    } tls13_master_secrets;
 
     mbedtls_ssl_tls13_handshake_secrets tls13_hs_secrets;
 #endif /* MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL */
@@ -1568,7 +1568,7 @@
 static inline unsigned mbedtls_ssl_tls13_check_kex_modes( mbedtls_ssl_context *ssl,
                                                           int kex_modes_mask )
 {
-    return( ( ssl->handshake->tls1_3_kex_modes & kex_modes_mask ) == 0 );
+    return( ( ssl->handshake->tls13_kex_modes & kex_modes_mask ) == 0 );
 }
 
 static inline int mbedtls_ssl_tls13_psk_enabled( mbedtls_ssl_context *ssl )
@@ -1678,7 +1678,7 @@
 int mbedtls_ssl_tls13_write_sig_alg_ext( mbedtls_ssl_context *ssl,
                                          unsigned char *buf,
                                          unsigned char *end,
-                                         size_t *olen);
+                                         size_t *out_len);
 
 #endif /* MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */