Support the legacy "mmu-masters" devicetree bindings


Linux Kernel Configuration
└─>Device Drivers
└─>IOMMU Hardware Support
└─>Device Tree and Open Firmware support
└─>Support the legacy "mmu-masters" devicetree bindings
In linux kernel since version 5.1 (release Date: 2019-05-05)  
Support for the badly designed and deprecated "mmu-masters"
devicetree bindings. This allows some DMA masters to attach
to the SMMU but does not provide any support via the DMA API.
If you're lucky, you might be able to get VFIO up and running.

If you say Y here then you'll make me very sad. Instead, say N
and move your firmware to the utopian future that was 2016.