vfio/pds: Fix memory leak in pds_vfio_dirty_enable()

pds_vfio_dirty_enable() allocates memory for region_info. If
interval_tree_iter_first() returns NULL, the function returns -EINVAL
immediately without freeing the allocated memory, causing a memory leak.

Fix this by jumping to the out_free_region_info label to ensure
region_info is freed.

Fixes: 2e7c6fe ("vfio/pds: Add multi-region support")
Signed-off-by: Zilin Guan <zilin@seu.edu.cn>
Link: https://lore.kernel.org/r/20251225143150.1117366-1-zilin@seu.edu.cn
Signed-off-by: Alex Williamson <alex@shazbot.org>

Author: GoodLuck612

drivers/vfio/pci/pds/dirty.c

@@ -292,8 +292,11 @@ static int pds_vfio_dirty_enable(struct pds_vfio_pci_device *pds_vfio,
 	len = num_ranges * sizeof(*region_info);
 
 	node = interval_tree_iter_first(ranges, 0, ULONG_MAX);
-	if (!node)
-		return -EINVAL;
+	if (!node) {
+		err = -EINVAL;
+		goto out_free_region_info;
+	}
+
 	for (int i = 0; i < num_ranges; i++) {
 		struct pds_lm_dirty_region_info *ri = &region_info[i];
 		u64 region_size = node->last - node->start + 1;