tls13: Use MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK.*ENABLED

Use MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_PSK_ENABLED
instead of MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED to guard
code specific to one of the TLS 1.3 key exchange mode with
PSK.

Signed-off-by: Ronald Cron <ronald.cron@arm.com>
diff --git a/library/ssl_tls13_client.c b/library/ssl_tls13_client.c
index c44399e..acac231 100644
--- a/library/ssl_tls13_client.c
+++ b/library/ssl_tls13_client.c
@@ -602,7 +602,7 @@
     return( 0 );
 }
 
-#if defined(MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED)
+#if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_PSK_ENABLED)
 /*
  * ssl_tls13_write_psk_key_exchange_modes_ext() structure:
  *
@@ -1112,8 +1112,7 @@
 
     return( 0 );
 }
-
-#endif /* MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED */
+#endif /* MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_PSK_ENABLED */
 
 int mbedtls_ssl_tls13_write_client_hello_exts( mbedtls_ssl_context *ssl,
                                                unsigned char *buf,
@@ -1151,7 +1150,7 @@
         p += ext_len;
     }
 
-#if defined(MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED)
+#if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_PSK_ENABLED)
     /* For PSK-based key exchange we need the pre_shared_key extension
      * and the psk_key_exchange_modes extension.
      *
@@ -1165,7 +1164,7 @@
     if( ret != 0 )
         return( ret );
     p += ext_len;
-#endif /* MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED */
+#endif
 
     *out_len = p - buf;
 
@@ -1681,7 +1680,7 @@
                     goto cleanup;
                 break;
 
-#if defined(MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED)
+#if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_PSK_ENABLED)
             case MBEDTLS_TLS_EXT_PRE_SHARED_KEY:
                 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found pre_shared_key extension" ) );
                 if( is_hrr )
@@ -1698,7 +1697,7 @@
                     return( ret );
                 }
                 break;
-#endif /* MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED */
+#endif
 
             case MBEDTLS_TLS_EXT_KEY_SHARE:
                 MBEDTLS_SSL_DEBUG_MSG( 3, ( "found key_shares extension" ) );