mwifiex: correction in MSDU padding logic

Padding arithmetic will always work for MSDUs provided first MSDU
ends on 4-byte boundary. Fixing it by making sure that all MSDU ends
on 4-byte boundary.
Signed-off-by: Yogesh Ashok Powar <yogeshp@marvell.com>
Signed-off-by: Amitkumar Karwar <akarwar@marvell.com>
Signed-off-by: Kiran Divekar <dkiran@marvell.com>
Signed-off-by: Bing Zhao <bzhao@marvell.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/mwifiex/11n_aggr.c

@@ -82,8 +82,8 @@ mwifiex_11n_form_amsdu_pkt(struct sk_buff *skb_aggr,
 	/* Add payload */
 	memcpy(skb_put(skb_aggr, skb_src->len), skb_src->data, skb_src->len);
 
-	*pad = (((skb_src->len + LLC_SNAP_LEN) & 3)) ? (4 - (((skb_src->len +
-						      LLC_SNAP_LEN)) & 3)) : 0;
+	/* Add padding for new MSDU to start from 4 byte boundary */
+	*pad = (4 - ((unsigned long)skb_aggr->tail & 0x3)) % 4;
 
 	return skb_aggr->len + *pad;
 }