PCI: Rename PCI_IRQ_LEGACY to PCI_IRQ_INTX

PCI: Rename PCI_IRQ_LEGACY to PCI_IRQ_INTX

Rename PCI_IRQ_LEGACY to PCI_IRQ_INTX to be more explicit about the type
of IRQ being referenced as well as to match the PCI specifications
terms. Redefine PCI_IRQ_LEGACY as an alias to PCI_IRQ_INTX to avoid the
need for doing the renaming tree-wide. New drivers and new code should
now prefer using PCI_IRQ_INTX instead of PCI_IRQ_LEGACY.

Link: https://lore.kernel.org/r/20231122060406.14695-2-dlemoal@kernel.org
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Reviewed-by: Serge Semin <fancer.lancer@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>