PCI: cadence: Extract link setup sequence from cdns_pcie_host_setup()

The function cdns_pcie_host_setup() mixes probe structure and link setup.

The link setup must be done during the resume sequence. So extract it from
cdns_pcie_host_setup() and create a dedicated function.

Link: https://lore.kernel.org/linux-pci/20240102-j7200-pcie-s2r-v7-1-a2f9156da6c3@bootlin.com


Signed-off-by: Thomas Richard <thomas.richard@bootlin.com>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Reviewed-by: Siddharth Vadapalli <s-vadapalli@ti.com>