In the commit 4f956c97d26b ("iommu/mediatek: Move domain_finalise into
attach_device"), I overlooked the sharing pgtable case.
After that commit, the "data" in the mtk_iommu_domain_finalise always is
the data of the current IOMMU HW. Fix this for the sharing pgtable case.
Only affect mt2712 which is the only SoC that share pgtable currently.
Fixes: 4f956c97d26b ("iommu/mediatek: Move domain_finalise into attach_device")
Signed-off-by: Yong Wu <yong.wu@xxxxxxxxxxxx>