accel/amdxdna: Allow forcing IOVA-based DMA via module parameter

accel/amdxdna: Allow forcing IOVA-based DMA via module parameter

The amdxdna driver normally performs DMA using userspace virtual address
plus PASID. For debugging and validation purposes, add a module parameter,
force_iova, to force DMA to go through IOMMU IOVA mapping.

When force_iova=1 is set, the driver will allocate and map DMA buffers
using IOVA.

Reviewed-by: Mario Limonciello (AMD) <superm1@kernel.org>
Signed-off-by: Lizhi Hou <lizhi.hou@amd.com>
Link: https://patch.msgid.link/20260126193001.1400545-1-lizhi.hou@amd.com