PCI: Enable PCI_DOMAINS along with generic PCI host controller

The generic PCI host controller is often instantiated by hypervisors, and
they may add several of them or add them in addition to a physical host
controller like the Jailhouse hypervisor is doing.  Therefore, allow for
multiple domains so that we can handle them all.
Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

drivers/pci/host/Kconfig

@@ -68,6 +68,7 @@ config PCI_HOST_GENERIC
 	depends on (ARM || ARM64) && OF
 	select PCI_HOST_COMMON
 	select IRQ_DOMAIN
+	select PCI_DOMAINS
 	help
 	  Say Y here if you want to support a simple generic PCI host
 	  controller, such as the one emulated by kvmtool.