PCI: brcmstb: Enable 7712 SoCs

PCI: brcmstb: Enable 7712 SoCs

The Broadcom STB 7712 is the sibling chip of the RPi 5 (2712). It has
one PCIe controller with a single port, supports gen2 and one lane only.

The current revision of the chip is "C0" or "C1".

Link: https://lore.kernel.org/linux-pci/20240815225731.40276-14-james.quinlan@broadcom.com
Signed-off-by: Jim Quinlan <james.quinlan@broadcom.com>
[kwilczynski: commit log]
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: Stanimir Varbanov <svarbanov@suse.de>