iommu/mediatek: Fix compatible typo for mediatek,mt6893-iommu-mm

Fix the "mediatek.mt6893-iommu-mm" compatible string typo, as the
dot was actually meant to be a comma: "mediatek,mt6893-iommu-mm".

Fixes: f6a1e89a ("iommu/mediatek: Add support for Dimensity 1200 MT6893 MM IOMMU")
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20250521151548.185910-1-angelogioacchino.delregno@collabora.com


Signed-off-by: Joerg Roedel <jroedel@suse.de>