This is needed to support non-PCI devices like memory-mapped
display controllers.
Split-out some initialization code from iommu_ctx_alloc() into
iommu_ctx_init() method so we could pass controller's MD-data
obtained from DTS to the driver prior to a CTX initialization.
Tested on Morello SoC.
Sponsored by: UKRI
One of the SMMU interrupt lines (priq) is optional and may be ommited in FDT.
Tested on ARM Morello Board, which has three SMMU units: first two have four
interrupt lines, last one has three interrupt lines.
Sponsored by: UKRI
