Remove role="search" attribute for get_search_form()

function remove_role_search($role)

{

    $result = array();

    preg_match_all('|role="[^"]*"|U', $role, $result);

    foreach ($result[0] as $role_tag) {

        $role = str_replace($role_tag, '', $role);

    }

    return $role;

}

add_filter('get_search_form', 'remove_role_search');