target/iscsi: Fix mutual CHAP auth on big-endian arches

See https://bugzilla.redhat.com/show_bug.cgi?id=916290

Used a temp var since we take its address in sg_init_one.
Signed-off-by: Andy Grover <agrover@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

drivers/target/iscsi/iscsi_target_auth.c

@@ -166,6 +166,7 @@ static int chap_server_compute_md5(
 {
 	char *endptr;
 	unsigned long id;
+	unsigned char id_as_uchar;
 	unsigned char digest[MD5_SIGNATURE_SIZE];
 	unsigned char type, response[MD5_SIGNATURE_SIZE * 2 + 2];
 	unsigned char identifier[10], *challenge = NULL;
@@ -355,7 +356,9 @@ static int chap_server_compute_md5(
 		goto out;
 	}
 
-	sg_init_one(&sg, &id, 1);
+	/* To handle both endiannesses */
+	id_as_uchar = id;
+	sg_init_one(&sg, &id_as_uchar, 1);
 	ret = crypto_hash_update(&desc, &sg, 1);
 	if (ret < 0) {
 		pr_err("crypto_hash_update() failed for id\n");