iommu/tegra: Fix incorrect size calculation

This driver uses a mixture of ways to get the size of a PTE,
tegra_smmu_set_pde() did it as sizeof(*pd) which became wrong when pd
switched to a struct tegra_pd.

Switch pd back to a u32* in tegra_smmu_set_pde() so the sizeof(*pd)
returns 4.

Fixes: 50568f87d1e2 ("iommu/terga: Do not use struct page as the handle for as->pd memory")
Reported-by: Diogo Ivo <[e-mail]>
Closes: https://lore.kernel.org/all/[e-mail]/
Signed-off-by: Jason Gunthorpe <[e-mail]>
Acked-by: Thierry Reding <[e-mail]>
Reviewed-by: Jerry Snitselaar <[e-mail]>
Tested-by: Diogo Ivo <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Joerg Roedel <[e-mail]>

drivers/iommu/tegra-smmu.c

···
 {
 	unsigned int pd_index = iova_pd_index(iova);
 	struct tegra_smmu *smmu = as->smmu;
-	struct tegra_pd *pd = as->pd;
+	u32 *pd = &as->pd->val[pd_index];
 	unsigned long offset = pd_index * sizeof(*pd);
 
 	/* Set the page directory entry first */
-	pd->val[pd_index] = value;
+	*pd = value;
 
 	/* The flush the page directory entry from caches */
 	dma_sync_single_range_for_device(smmu->dev, as->pd_dma, offset,