ip/vxlan: fix display of maxaddress option

Parenthesis are required else maxaddr value is a bool and thus output is always
1 when the option is set.

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
diff --git a/ip/iplink_vxlan.c b/ip/iplink_vxlan.c
index 8aa25cd..d92cfe8 100644
--- a/ip/iplink_vxlan.c
+++ b/ip/iplink_vxlan.c
@@ -361,7 +361,7 @@
 	}
 
 	if (tb[IFLA_VXLAN_LIMIT] &&
-	    (maxaddr = rta_getattr_u32(tb[IFLA_VXLAN_LIMIT]) != 0))
+	    ((maxaddr = rta_getattr_u32(tb[IFLA_VXLAN_LIMIT])) != 0))
 		    fprintf(f, "maxaddr %u ", maxaddr);
 }