iommu/arm-smmu: Fix the index calculation of strtab

The element size of cfg->strtab is just one DWORD, so we should use a
multiply operation instead of a shift when calculating the level 1
index.
Signed-off-by: NZhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

drivers/iommu/arm-smmu-v3.c

@@ -1064,7 +1064,7 @@ static int arm_smmu_init_l2_strtab(struct arm_smmu_device *smmu, u32 sid)
 		return 0;
 
 	size = 1 << (STRTAB_SPLIT + ilog2(STRTAB_STE_DWORDS) + 3);
-	strtab = &cfg->strtab[sid >> STRTAB_SPLIT << STRTAB_L1_DESC_DWORDS];
+	strtab = &cfg->strtab[(sid >> STRTAB_SPLIT) * STRTAB_L1_DESC_DWORDS];
 
 	desc->span = STRTAB_SPLIT + 1;
 	desc->l2ptr = dma_zalloc_coherent(smmu->dev, size, &desc->l2ptr_dma,