iommu/io-pgtable-arm-v7s: Quad lvl1 pgtable for MediaTek

The standard input iova bits is 32. MediaTek quad the lvl1 pagetable
(4 * lvl1). No change for lvl2 pagetable. Then the iova bits can reach
34bit.

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/20210111111914.22211-14-yong.wu@mediatek.com
Signed-off-by: Will Deacon <will@kernel.org>