PCI: rockchip-ep: Refactor rockchip_pcie_ep_probe() MSI-X hiding

PCI: rockchip-ep: Refactor rockchip_pcie_ep_probe() MSI-X hiding

Move the code in rockchip_pcie_ep_probe() to hide the MSI-X capability
to its own function, rockchip_pcie_ep_hide_broken_msix_cap().

No functional changes.

Link: https://lore.kernel.org/r/20241017015849.190271-10-dlemoal@kernel.org
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>