iommu/io-pgtable-arm-v7s: Use ias to check the valid iova in unmap

Use the ias for the valid iova checking in arm_v7s_unmap. This is a
preparing patch for supporting iova 34bit for MediaTek.
Signed-off-by: Yong Wu <yong.wu@mediatek.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Reviewed-by: Tomasz Figa <tfiga@chromium.org>
Link: https://lore.kernel.org/r/20210111111914.22211-10-yong.wu@mediatek.comSigned-off-by: Will Deacon <will@kernel.org>

drivers/iommu/io-pgtable-arm-v7s.c

@@ -711,7 +711,7 @@ static size_t arm_v7s_unmap(struct io_pgtable_ops *ops, unsigned long iova,
 {
 	struct arm_v7s_io_pgtable *data = io_pgtable_ops_to_data(ops);
 
-	if (WARN_ON(upper_32_bits(iova)))
+	if (WARN_ON(iova >= (1ULL << data->iop.cfg.ias)))
 		return 0;
 
 	return __arm_v7s_unmap(data, gather, iova, size, 1, data->pgd);