cxgb3: avoid potential memory leak.

Add consistency in alloc_ring() parameter checking
to avoid potential memory leaks.
alloc_ring() callers are correct fo far.
Signed-off-by: Divy Le Ray <divy@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/cxgb3/sge.c

@@ -549,16 +549,15 @@ static void *alloc_ring(struct pci_dev *pdev, size_t nelem, size_t elem_size,
 
 	if (!p)
 		return NULL;
-	if (sw_size) {
+	if (sw_size && metadata) {
 		s = kcalloc(nelem, sw_size, GFP_KERNEL);
 
 		if (!s) {
 			dma_free_coherent(&pdev->dev, len, p, *phys);
 			return NULL;
 		}
-	}
-	if (metadata)
 		*(void **)metadata = s;
+	}
 	memset(p, 0, len);
 	return p;
 }