batman-adv: fix header alignment by unrolling batadv_header

The size of the batadv_header of 3 is problematic on some architectures
which automatically pad all structures to a 32 bit boundary. To not lose
performance by packing this struct, better embed it into the various
host structures.

Reported-by: Russell King <linux@arm.linux.org.uk>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Antonio Quartulli <antonio@meshcoding.com>
diff --git a/net/batman-adv/fragmentation.c b/net/batman-adv/fragmentation.c
index 271d321..6ddb614 100644
--- a/net/batman-adv/fragmentation.c
+++ b/net/batman-adv/fragmentation.c
@@ -355,7 +355,7 @@
 		batadv_add_counter(bat_priv, BATADV_CNT_FRAG_FWD_BYTES,
 				   skb->len + ETH_HLEN);
 
-		packet->header.ttl--;
+		packet->ttl--;
 		batadv_send_skb_packet(skb, neigh_node->if_incoming,
 				       neigh_node->addr);
 		ret = true;
@@ -444,9 +444,9 @@
 		goto out_err;
 
 	/* Create one header to be copied to all fragments */
-	frag_header.header.packet_type = BATADV_UNICAST_FRAG;
-	frag_header.header.version = BATADV_COMPAT_VERSION;
-	frag_header.header.ttl = BATADV_TTL;
+	frag_header.packet_type = BATADV_UNICAST_FRAG;
+	frag_header.version = BATADV_COMPAT_VERSION;
+	frag_header.ttl = BATADV_TTL;
 	frag_header.seqno = htons(atomic_inc_return(&bat_priv->frag_seqno));
 	frag_header.reserved = 0;
 	frag_header.no = 0;