b43legacy: fix B43legacy_WARN_ON macro

Fix the B43legacy_WARN_ON macro so that it will evaluate expressions.

Signed-off-by: Stefano Brivio <stefano.brivio@polimi.it>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/b43legacy/main.c b/drivers/net/wireless/b43legacy/main.c
index 62e679a..82953dd 100644
--- a/drivers/net/wireless/b43legacy/main.c
+++ b/drivers/net/wireless/b43legacy/main.c
@@ -1068,10 +1068,8 @@
 	B43legacy_WARN_ON(ie_start != offsetof(struct ieee80211_mgmt,
 					       u.beacon.variable));
 
-	if (src_size < ie_start) {
-		B43legacy_WARN_ON(1);
+	if (B43legacy_WARN_ON(src_size < ie_start))
 		return NULL;
-	}
 
 	dest_data = kmalloc(src_size, GFP_ATOMIC);
 	if (unlikely(!dest_data))