iommu/mediatek: Delete the leaf in the tlb_flush

In our tlb range flush, we don't care the "leaf". Remove it to simplify
the code. no functional change.

"granule" also is unnecessary for us, Keep it satisfy the format of
tlb_flush_walk.

Signed-off-by: Yong Wu <yong.wu@mediatek.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>