CIPSO: Fix unaligned memory access in cipso_v4_gentag_hdr

We need to use put_unaligned when writing 32-bit DOI value
in cipso_v4_gentag_hdr to avoid unaligned memory access.

v2: unneeded type cast removed as Ondrej Mosnacek suggested.
Signed-off-by: Sergey Nazarov <s-nazarov@yandex.ru>
Acked-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/cipso_ipv4.c

@@ -1153,7 +1153,7 @@ static void cipso_v4_gentag_hdr(const struct cipso_v4_doi *doi_def,
 {
 	buf[0] = IPOPT_CIPSO;
 	buf[1] = CIPSO_V4_HDR_LEN + len;
-	*(__be32 *)&buf[2] = htonl(doi_def->doi);
+	put_unaligned_be32(doi_def->doi, &buf[2]);
 }
 
 /**