PCI: microchip: Rename interrupt related functions

Rename mc_* to plda_* for IRQ functions and related IRQ domain ops data
instances.

MSI, INTx interrupt code and IRQ init code can all be re-used.

Link: https://lore.kernel.org/linux-pci/20240328091835.14797-11-minda.chen@starfivetech.comSigned-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>