libertas_tf: remove set but not used variable 'flags'

Fixes gcc '-Wunused-but-set-variable' warning:

drivers/net/wireless/marvell/libertas_tf/main.c: In function 'lbtf_rx':
drivers/net/wireless/marvell/libertas_tf/main.c:554:15: warning:
 variable 'flags' set but not used [-Wunused-but-set-variable]

It never used and can be removed.
Signed-off-by: NYueHaibing <yuehaibing@huawei.com>
Acked-by: NSteve deRosier <derosier@cal-sierra.com>
Signed-off-by: NKalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/marvell/libertas_tf/main.c

@@ -550,7 +550,6 @@ int lbtf_rx(struct lbtf_private *priv, struct sk_buff *skb)
 	struct ieee80211_rx_status stats;
 	struct rxpd *prxpd;
 	int need_padding;
-	unsigned int flags;
 	struct ieee80211_hdr *hdr;
 
 	lbtf_deb_enter(LBTF_DEB_RX);
@@ -571,7 +570,6 @@ int lbtf_rx(struct lbtf_private *priv, struct sk_buff *skb)
 	skb_pull(skb, sizeof(struct rxpd));
 
 	hdr = (struct ieee80211_hdr *)skb->data;
-	flags = le32_to_cpu(*(__le32 *)(skb->data + 4));
 
 	need_padding = ieee80211_is_data_qos(hdr->frame_control);
 	need_padding ^= ieee80211_has_a4(hdr->frame_control);