dt-bindings: PCI: qcom: Add SC8280XP to binding

Add the SC8280XP platform to the binding.

SC8280XP use four host interrupts for MSI routing so remove the obsolete
comment referring to newer chipsets supporting one or eight interrupts
(e.g. for backwards compatibility).

Link: https://lore.kernel.org/r/20220714071348.6792-3-johan+linaro@kernel.org


Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Acked-by: Stanimir Varbanov <svarbanov@mm-sol.com>