Staging: rtl8192u: ieee80211: add missing parentheses

not(!) has a higher precedence than bit and(&).
Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/rtl8192u/ieee80211/ieee80211_wx.c

@@ -718,7 +718,7 @@ int ieee80211_wx_get_encode_ext(struct ieee80211_device *ieee,
 	} else
 		idx = ieee->tx_keyidx;
 
-	if (!ext->ext_flags & IW_ENCODE_EXT_GROUP_KEY &&
+	if (!(ext->ext_flags & IW_ENCODE_EXT_GROUP_KEY) &&
 	    ext->alg != IW_ENCODE_ALG_WEP)
 		if (idx != 0 || ieee->iw_mode != IW_MODE_INFRA)
 			return -EINVAL;