iommu: apple-dart: Remove unnecessary NULL check before free_io_pgtable_ops()

free_io_pgtable_ops() checks for NULL pointers internally.
Remove unneeded NULL check here.

Signed-off-by: Chen Ni <nichen@iscas.ac.cn>
Link: https://lore.kernel.org/r/20250422072511.1334243-1-nichen@iscas.ac.cn
Signed-off-by: Joerg Roedel <jroedel@suse.de>

Author: Chen Ni

drivers/iommu/apple-dart.c

@@ -776,8 +776,7 @@ static void apple_dart_domain_free(struct iommu_domain *domain)
 {
 	struct apple_dart_domain *dart_domain = to_dart_domain(domain);
 
-	if (dart_domain->pgtbl_ops)
-		free_io_pgtable_ops(dart_domain->pgtbl_ops);
+	free_io_pgtable_ops(dart_domain->pgtbl_ops);
 
 	kfree(dart_domain);
 }