swiotlb: no need to check return value of debugfs_create functions

When calling debugfs functions, there is no need to ever check the
return value.  The function can work or not, but the code logic should
never do something different based on this.

Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: iommu@lists.linux-foundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20190612144314.GA16803@kroah.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

kernel/dma/swiotlb.c

@@ -696,29 +696,12 @@ bool is_swiotlb_active(void)
 
 static int __init swiotlb_create_debugfs(void)
 {
-	struct dentry *d_swiotlb_usage;
-	struct dentry *ent;
-
-	d_swiotlb_usage = debugfs_create_dir("swiotlb", NULL);
-
-	if (!d_swiotlb_usage)
-		return -ENOMEM;
-
-	ent = debugfs_create_ulong("io_tlb_nslabs", 0400,
-				   d_swiotlb_usage, &io_tlb_nslabs);
-	if (!ent)
-		goto fail;
-
-	ent = debugfs_create_ulong("io_tlb_used", 0400,
-				   d_swiotlb_usage, &io_tlb_used);
-	if (!ent)
-		goto fail;
+	struct dentry *root;
 
+	root = debugfs_create_dir("swiotlb", NULL);
+	debugfs_create_ulong("io_tlb_nslabs", 0400, root, &io_tlb_nslabs);
+	debugfs_create_ulong("io_tlb_used", 0400, root, &io_tlb_used);
 	return 0;
-
-fail:
-	debugfs_remove_recursive(d_swiotlb_usage);
-	return -ENOMEM;
 }
 
 late_initcall(swiotlb_create_debugfs);