hw/riscv/virt-acpi-build: Add support for RIMT

hw/riscv/virt-acpi-build: Add support for RIMT

RISC-V IO Mapping Table (RIMT) is a new static ACPI table used to
communicate IOMMU information to the OS. Add support for creating this
table when the IOMMU is present. The specification is frozen and
available at [1].

[1] - https://github.com/riscv-non-isa/riscv-acpi-rimt/releases/download/v0.99/rimt-spec.pdf

Signed-off-by: Sunil V L <sunilvl@ventanamicro.com>
Reviewed-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Message-ID: <20250322043139.2003479-3-sunilvl@ventanamicro.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>