buffer: remove unneeded eslint-disable comment

lib/buffer.js uses a function declaration for `Buffer`. So it never
uses an instance of `Buffer` in the global scope. Therefore the
disabling of the `require-buffer` custom rule is not needed. Remove the
comment.

PR-URL: #11906
Reviewed-By: James M Snell <[email protected]>
Reviewed-By: Colin Ihrig <[email protected]>
Reviewed-By: Luigi Pinca <[email protected]>
Reviewed-By: Roman Reiss <[email protected]>

Author: Trott

lib/buffer.js

@@ -1,4 +1,3 @@
-/* eslint-disable require-buffer */
 'use strict';
 
 const binding = process.binding('buffer');