Claude review: accel/qda: Add DMA-backed GEM objects and memory manager integration

[Claude Code Review Bot <claude-review@example.com>]

Patch Review

- Dmitry asked: "Why are you not using drm_gem_dma_helper?" — this is a key question. The DRM subsystem provides `drm_gem_dma_object` and helpers specifically for DMA-backed GEM objects. Reimplementing this is unjustified without a clear explanation.

- **Namespace pollution**: Functions are not consistently named with the `qda_` prefix.

- **PID-based IOMMU device assignment**: The logic assigns IOMMU devices based on PID:
  - Dmitry asked: "What if there are two different FastRPC sessions within the same PID?" This is a real scenario (multi-threaded DSP applications).

- **Over-verbose logging** with debug enabled — Dmitry noted this independently.

- **Kernel-doc placement**: "Move the kerneldoc from the headers to the driver code, otherwise they are mostly ignored by the automatic validators."

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Generated by Claude Code Patch Reviewer