Din forespørgsel
$select = "INSERT INTO registro (nome, usuario, email, senha, cpf, rg)
VALUES (:nome, :usuario, email, :senha, :cpf, :rg)";
Efter ændring Mangler:i e-mail
$select = "INSERT INTO registro (nome, usuario, email, senha, cpf, rg)
VALUES (:nome, :usuario, :email, :senha, :cpf, :rg)";