iommu/io-pgtable-dart: Only set subpage protection disable for DART 1

Subpage protection can't be disabled on t6000-style darts,
as such the disable flag no longer applies, and probably
even affects something else.

Fixes: dc09fe1 ("iommu/io-pgtable-dart: Add DART PTE support for t6000")
Signed-off-by: Asahi Lina <lina@asahilina.net>
Signed-off-by: Sasha Finkelstein <fnkl.kernel@gmail.com>
Reviewed-by: Sven Peter <sven@svenpeter.dev>
Link: https://lore.kernel.org/r/20250219-dart2-no-sp-disable-v1-1-9f324cfa4e70@gmail.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>

Author: hoshinolina

drivers/iommu/io-pgtable-dart.c

@@ -135,7 +135,6 @@ static int dart_init_pte(struct dart_io_pgtable *data,
 	pte |= FIELD_PREP(APPLE_DART_PTE_SUBPAGE_START, 0);
 	pte |= FIELD_PREP(APPLE_DART_PTE_SUBPAGE_END, 0xfff);
 
-	pte |= APPLE_DART1_PTE_PROT_SP_DIS;
 	pte |= APPLE_DART_PTE_VALID;
 
 	for (i = 0; i < num_entries; i++)
@@ -211,6 +210,7 @@ static dart_iopte dart_prot_to_pte(struct dart_io_pgtable *data,
 	dart_iopte pte = 0;
 
 	if (data->iop.fmt == APPLE_DART) {
+		pte |= APPLE_DART1_PTE_PROT_SP_DIS;
 		if (!(prot & IOMMU_WRITE))
 			pte |= APPLE_DART1_PTE_PROT_NO_WRITE;
 		if (!(prot & IOMMU_READ))