batman-adv: Remove unnecessary parentheses

checkpatch introduced with commit 63b7c73ec86b ("checkpatch: add --strict
check for ifs with unnecessary parentheses") an additional test which
identifies some unnecessary parentheses.

Remove these unnecessary parentheses to avoid the warnings and to unify the
coding style slightly more.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
diff --git a/net/batman-adv/tp_meter.c b/net/batman-adv/tp_meter.c
index bfe8eff..4b90033 100644
--- a/net/batman-adv/tp_meter.c
+++ b/net/batman-adv/tp_meter.c
@@ -1206,7 +1206,7 @@
 
 	/* send the ack */
 	r = batadv_send_skb_to_orig(skb, orig_node, NULL);
-	if (unlikely(r < 0) || (r == NET_XMIT_DROP)) {
+	if (unlikely(r < 0) || r == NET_XMIT_DROP) {
 		ret = BATADV_TP_REASON_DST_UNREACHABLE;
 		goto out;
 	}