PCI: hisi: Add support for HiSilicon Hip06 PCIe host controllers

Add support for the HiSilicon Hip06 SoC.  Documentation has been updated to
include Hip06.  Add Gabriele Paoloni as maintainer of the driver.

Signed-off-by: Gabriele Paoloni <gabriele.paoloni@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Zhou Wang <wangzhou1@hisilicon.com>