How to Hide the "PHP Compatibility" Admin Menu

function plt_hide_php_compatibility_checker_menus() {
	//Hide the "Tools → PHP Compatibility" menu.
	remove_submenu_page('tools.php', 'wpe-php-compat');
}

add_action('admin_menu', 'plt_hide_php_compatibility_checker_menus', 11);

Where do I put this code?