swiotlb: simplify array allocation

Prefer kcalloc() to kzalloc(array_size()) for allocating an array.
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

kernel/dma/swiotlb.c

@@ -818,8 +818,7 @@ static int rmem_swiotlb_device_init(struct reserved_mem *rmem,
 		if (!mem)
 			return -ENOMEM;
 
-		mem->slots = kzalloc(array_size(sizeof(*mem->slots), nslabs),
-				     GFP_KERNEL);
+		mem->slots = kcalloc(nslabs, sizeof(*mem->slots), GFP_KERNEL);
 		if (!mem->slots) {
 			kfree(mem);
 			return -ENOMEM;