virtio: put paren around sizeof

Kernel coding style is to put paren around operand of sizeof.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index a3f3c66..4302f31 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -319,7 +319,7 @@
 
 	hdr_len = vi->hdr_len;
 	if (vi->mergeable_rx_bufs)
-		hdr_padded_len = sizeof *hdr;
+		hdr_padded_len = sizeof(*hdr);
 	else
 		hdr_padded_len = sizeof(struct padded_vnet_hdr);