src: remove unused macro in node_http2.h

PR-URL: #26204
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: James M Snell <jasnell@gmail.com>

Author: gengjiawen

src/node_http2.h

@@ -50,8 +50,6 @@ using performance::PerformanceEntry;
 #define MAX_MAX_HEADER_LIST_SIZE 16777215u
 #define DEFAULT_MAX_HEADER_LIST_PAIRS 128u
 
-#define MAX_BUFFER_COUNT 16
-
 enum nghttp2_session_type {
   NGHTTP2_SESSION_SERVER,
   NGHTTP2_SESSION_CLIENT