PCI: brcmstb: Set generation limit before PCIe link up

PCI: brcmstb: Set generation limit before PCIe link up

[ Upstream commit 72d36589c6b7bef6b30eb99fcb7082f72faca37f ]

When the user elects to limit the PCIe generation via the appropriate
devicetree property, apply the settings before the PCIe link up, not
after.

Fixes: c0452137034b ("PCI: brcmstb: Add Broadcom STB PCIe host controller driver")
Signed-off-by: Jim Quinlan <james.quinlan@broadcom.com>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20250214173944.47506-2-james.quinlan@broadcom.com
[kwilczynski: commit log]
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>