PCI: microchip: Add event irqchip field to host port and add PLDA irqchip

PCI: microchip: Add event irqchip field to host port and add PLDA irqchip

As the PLDA DT binding doc (Documentation/devicetree/bindings/pci/
plda,xpressrich3-axi-common.yaml) shows, PLDA PCIe contains an interrupt
controller.

Microchip PolarFire PCIe event IRQs include PLDA interrupts and PolarFire
additional interrupts. The interrupt irqchip ops includes ack/mask/unmask
interrupt ops, which will write correct registers.  Microchip PolarFire
PCIe additional interrupts require to write PolarFire SoC self-defined
registers. So Microchip PCIe event irqchip ops can not be re-used.

Microchip PolarFire PCIe additional interrupts (defined in
drivers/pci/controller/plda/pcie-microchip-host.c):

  EVENT_PCIE_L2_EXIT
  EVENT_PCIE_HOTRST_EXIT
  EVENT_PCIE_DLUP_EXIT
  EVENT_SEC_TX_RAM_SEC_ERR
  EVENT_SEC_RX_RAM_SEC_ERR
  ...

To support PLDA its own event IRQ process, implements PLDA irqchip ops and
add event irqchip field to struct pcie_plda_rp.

[kwilczynski: commit log]
Link: https://lore.kernel.org/linux-pci/20240328091835.14797-16-minda.chen@starfivetech.com
Signed-off-by: Minda Chen <minda.chen@starfivetech.com>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>