PCI: hisi: Fix deferred probing

The hisi_pcie_probe() function is incorrectly marked as __init, as Kconfig
tells us:

  WARNING: drivers/pci/host/built-in.o(.data+0x7780): Section mismatch in reference from the variable hisi_pcie_driver to the function .init.text:hisi_pcie_probe()

If the probe for this device gets deferred past the point where __init
functions are removed, or the device is unbound and then reattached to the
driver, we branch into uninitialized memory, which is bad.

Remove the __init annotation from hisi_pcie_probe() and
hisi_add_pcie_port().

Fixes: 500a1d9a ("PCI: hisi: Add HiSilicon SoC Hip05 PCIe driver")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Hanjun Guo <hanjun.guo@linaro.org>
Acked-by: Zhou Wang <wangzhou1@hisilicon.com>