hw/arm/smmu-common: IOMMU memory region and address space setup

We set up the infrastructure to enumerate all the PCI devices
attached to the SMMU and create an associated IOMMU memory
region and address space.

Those info are stored in SMMUDevice objects. The devices are
grouped according to the PCIBus they belong to. A hash table
indexed by the PCIBus pointer is used. Also an array indexed by
the bus number allows to find the list of SMMUDevices.

Signed-off-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Prem Mallappa <prem.mallappa@broadcom.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 1524665762-31355-3-git-send-email-eric.auger@redhat.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>