hw/pcie-pci-bridge: restrict to X86 and ARM

The PCIE-PCI bridge is specific to "pure" PCIe systems
(on QEMU we have X86 and ARM), it does not make sense to
have it in other archs.
Reported-by: NThomas Huth <thuth@redhat.com>
Signed-off-by: NMarcel Apfelbaum <marcel@redhat.com>
Reviewed-by: NThomas Huth <thuth@redhat.com>
Reviewed-by: NPhilippe Mathieu-Daudé <f4bug@amsat.org>
Tested-by: NPhilippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: NCornelia Huck <cohuck@redhat.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Tested-by: NYongbok Kim <yongbok.kim@mips.com>

hw/pci-bridge/Makefile.objs

-common-obj-y += pci_bridge_dev.o pcie_pci_bridge.o
-common-obj-$(CONFIG_PCIE_PORT) += pcie_root_port.o gen_pcie_root_port.o
+common-obj-y += pci_bridge_dev.o
+common-obj-$(CONFIG_PCIE_PORT) += pcie_root_port.o gen_pcie_root_port.o pcie_pci_bridge.o
 common-obj-$(CONFIG_PXB) += pci_expander_bridge.o
 common-obj-$(CONFIG_XIO3130) += xio3130_upstream.o xio3130_downstream.o
 common-obj-$(CONFIG_IOH3420) += ioh3420.o