mwifiex: fix memory leak issue for ibss join

For IBSS join if the requested SSID matches current SSID,
it returns without freeing the allocated beacon IE buffer.

Cc: <stable@vger.kernel.org> # 3.10+
Signed-off-by: Ujjal Roy <royujjal@gmail.com>
Signed-off-by: Bing Zhao <bzhao@marvell.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/mwifiex/sta_ioctl.c

@@ -319,8 +319,8 @@ int mwifiex_bss_start(struct mwifiex_private *priv, struct cfg80211_bss *bss,
 		if (bss_desc && bss_desc->ssid.ssid_len &&
 		    (!mwifiex_ssid_cmp(&priv->curr_bss_params.bss_descriptor.
 				       ssid, &bss_desc->ssid))) {
-			kfree(bss_desc);
-			return 0;
+			ret = 0;
+			goto done;
 		}
 
 		/* Exit Adhoc mode first */