PCI: Build setup-irq.o for arm64

ARM64 requires setup-irq.o to provide pci_fixup_irqs() implementation.  We
are adding this now to support the pci-host-generic host controller, but we
enable it for ARM64 PCI so that other host controllers can use this as
well.
Signed-off-by: Jayachandran C <jchandra@broadcom.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

drivers/pci/Makefile

@@ -33,6 +33,7 @@ obj-$(CONFIG_PCI_IOV) += iov.o
 #
 obj-$(CONFIG_ALPHA) += setup-irq.o
 obj-$(CONFIG_ARM) += setup-irq.o
+obj-$(CONFIG_ARM64) += setup-irq.o
 obj-$(CONFIG_UNICORE32) += setup-irq.o
 obj-$(CONFIG_SUPERH) += setup-irq.o
 obj-$(CONFIG_MIPS) += setup-irq.o