iommu/io-pgtable-arm: Re-use the pgtable walk for iova_to_phys

Re-use the generic pgtable walk path.

Signed-off-by: Rob Clark <robdclark@chromium.org>
Reviewed-by: Mostafa Saleh <smostafa@google.com>
Link: https://lore.kernel.org/r/20241210165127.600817-3-robdclark@gmail.com


Signed-off-by: Will Deacon <will@kernel.org>