iommu/mediatek: Fix share pgtable for iova over 4GB

In mt8192/mt8186, there is only one MM IOMMU that supports 16GB iova
space, which is shared by display, vcodec and camera. These two SoC use
one pgtable and have not the flag SHARE_PGTABLE, we should also keep
share pgtable for this case.

In mtk_iommu_domain_finalise, MM IOMMU always share pgtable, thus remove
the flag SHARE_PGTABLE checking. Infra IOMMU always uses independent
pgtable.

Fixes: cf69ef46

 ("iommu/mediatek: Fix two IOMMU share pagetable issue")
Reported-by: Laura Nao <laura.nao@collabora.com>
Closes: https://lore.kernel.org/linux-iommu/20230818154156.314742-1-laura.nao@collabora.com/
Signed-off-by: Yong Wu <yong.wu@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Tested-by: Laura Nao <laura.nao@collabora.com>
Link: https://lore.kernel.org/r/20230819081443.8333-1-yong.wu@mediatek.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>