xfs: clean up xfs_buf_item_get_format return value

The only thing that can cause a nonzero return from
xfs_buf_item_get_format is if the kmem_alloc fails, which it can't.
Get rid of all the unnecessary error handling.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

fs/xfs/xfs_buf_item.c

@@ -688,7 +688,7 @@ static const struct xfs_item_ops xfs_buf_item_ops = {
 	.iop_push	= xfs_buf_item_push,
 };
 
-STATIC int
+STATIC void
 xfs_buf_item_get_format(
 	struct xfs_buf_log_item	*bip,
 	int			count)
@@ -698,14 +698,11 @@ xfs_buf_item_get_format(
 
 	if (count == 1) {
 		bip->bli_formats = &bip->__bli_format;
-		return 0;
+		return;
 	}
 
 	bip->bli_formats = kmem_zalloc(count * sizeof(struct xfs_buf_log_format),
 				0);
-	if (!bip->bli_formats)
-		return -ENOMEM;
-	return 0;
 }
 
 STATIC void
@@ -731,7 +728,6 @@ xfs_buf_item_init(
 	struct xfs_buf_log_item	*bip = bp->b_log_item;
 	int			chunks;
 	int			map_size;
-	int			error;
 	int			i;
 
 	/*
@@ -760,13 +756,7 @@ xfs_buf_item_init(
 	 * Discontiguous buffer support follows the layout of the underlying
 	 * buffer. This makes the implementation as simple as possible.
 	 */
-	error = xfs_buf_item_get_format(bip, bp->b_map_count);
-	ASSERT(error == 0);
-	if (error) {	/* to stop gcc throwing set-but-unused warnings */
-		kmem_cache_free(xfs_buf_item_zone, bip);
-		return error;
-	}
-
+	xfs_buf_item_get_format(bip, bp->b_map_count);
 
 	for (i = 0; i < bip->bli_format_count; i++) {
 		chunks = DIV_ROUND_UP(BBTOB(bp->b_maps[i].bm_len),