rsi: release skb if rsi_prepare_beacon fails

In rsi_send_beacon, if rsi_prepare_beacon fails the allocated skb should
be released.

Signed-off-by: Navid Emamdoost <navid.emamdoost@gmail.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/rsi/rsi_91x_mgmt.c

@@ -1756,6 +1756,7 @@ static int rsi_send_beacon(struct rsi_common *common)
 		skb_pull(skb, (64 - dword_align_bytes));
 	if (rsi_prepare_beacon(common, skb)) {
 		rsi_dbg(ERR_ZONE, "Failed to prepare beacon\n");
+		dev_kfree_skb(skb);
 		return -EINVAL;
 	}
 	skb_queue_tail(&common->tx_queue[MGMT_BEACON_Q], skb);