iommu/mediatek: Support up to 34bit iova in tlb flush

If the iova is 34bit, the iova[32][33] is the bit0/1 in the tlb flush
register. Add a new macro for this.

In the macro, since (iova + size - 1) may be end with 0xfff, then the
bit0/1 always is 1, thus add a mask.

Signed-off-by: Yong Wu <yong.wu@mediatek.com>
Reviewed-by: Tomasz Figa <tfiga@chromium.org>
Link: https://lore.kernel.org/r/20210111111914.22211-22-yong.wu@mediatek.com
Signed-off-by: Will Deacon <will@kernel.org>