drm/msm: use for_each_sgtable_sg to iterate over scatterlist

[ Upstream commit 62b5e322 ]

The dma_map_sgtable() call (used to invalidate cache) overwrites sgt->nents
with 1, so msm_iommu_pagetable_map maps only the first physical segment.

To fix this problem use for_each_sgtable_sg(), which uses orig_nents.

Fixes: b145c6e6

 ("drm/msm: Add support to create a local pagetable")
Signed-off-by: Jonathan Marek <jonathan@marek.ca>
Link: https://lore.kernel.org/r/20220613221019.11399-1-jonathan@marek.ca
Signed-off-by: Rob Clark <robdclark@chromium.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>