e1000e: checkpatch error - macro panethesis

ERROR: Macros with complex values should be enclosed in parenthesis

Signed-off-by: Bruce Allan <bruce.w.allan@intel.com>
Tested-by: Emil Tantilov <emil.s.tantilov@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
diff --git a/drivers/net/e1000e/netdev.c b/drivers/net/e1000e/netdev.c
index a45dafd..ec7b77f 100644
--- a/drivers/net/e1000e/netdev.c
+++ b/drivers/net/e1000e/netdev.c
@@ -1325,7 +1325,7 @@
 				goto next_desc;
 		}
 
-#define rxtop rx_ring->rx_skb_top
+#define rxtop (rx_ring->rx_skb_top)
 		if (!(status & E1000_RXD_STAT_EOP)) {
 			/* this descriptor is only the beginning (or middle) */
 			if (!rxtop) {