feat(riscv/iommu): update support for RISC-V IOMMU Device Directory Table

[malejo97]

This PR introduces multiple updates to RISC-V IOMMU support regarding the Device Directory Table.

Changes:

• Add support for IOMMU implementations without MSI translation, where each DC is 32-bytes wide;
• Add support for multi-level device directory tables;
• Add mechanism for dynamic selection of IOMMU mode based on the IDs of the devices embedded in the platform.

Validation

• Tested on CVA6-based SoC w/IOMMU and x4 DMA devices with different ID widths
• Linux v6.3
• OpenSBI v1.0