arm64: Teach bus_dma on arm64 about NUMA

[andrew]

Summary

When allocating memory we should try to allocate from the NUMA node
closest to the device to reduce cross domain memory traffic. Teach the
arm64 bus_dma code to do this.

While here use mallocarray to guard against an unlikely integer
overflow.

Sponsored by: Arm Ltd

[markj]

Nothing is setting the domain for tags belonging to the root bus devices. On amd64 this happens in acpi_pcib_acpi_attach() but I believe that implementation isn't used on arm64.

sys/arm64/arm64/busdma_bounce.c

411

522

588

Why did this change?

[andrew]

See D42186 for the pci change

sys/arm64/arm64/busdma_bounce.c

588

Because I switched to malloc_domainset_aligned so we could explicitly set the alignment.

I can sync the above comment with x86 as needed.

[andrew]

Remove unneeded casts and update the comment in bounce_bus_dmamem_alloc