[ipv6] Treat sin6_scope_id consistently

sin6_scope_id is never exposed outside of the local system, and so
should be a native-endian quantity.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/net/ipv6.c

 			 sizeof ( iphdr->src ) );
 	}
 	if ( ( ! IN6_IS_ADDR_MULTICAST ( next_hop ) ) &&
-	     ( ( miniroute = ipv6_route ( ntohl ( sin6_dest->sin6_scope_id ),
+	     ( ( miniroute = ipv6_route ( sin6_dest->sin6_scope_id,
 					  &next_hop ) ) != NULL ) ) {
 		memcpy ( &iphdr->src, &miniroute->address,
 			 sizeof ( iphdr->src ) );
 	src.sin6.sin6_family = AF_INET6;
 	memcpy ( &src.sin6.sin6_addr, &iphdr->src,
 		 sizeof ( src.sin6.sin6_addr ) );
-	src.sin6.sin6_scope_id = htonl ( netdev->index );
+	src.sin6.sin6_scope_id = netdev->index;
 	memset ( &dest, 0, sizeof ( dest ) );
 	dest.sin6.sin6_family = AF_INET6;
 	memcpy ( &dest.sin6.sin6_addr, &iphdr->dest,
 		 sizeof ( dest.sin6.sin6_addr ) );
-	dest.sin6.sin6_scope_id = htonl ( netdev->index );
+	dest.sin6.sin6_scope_id = netdev->index;
 	iob_pull ( iobuf, hdrlen );
 	pshdr_csum = ipv6_pshdr_chksum ( iphdr, iob_len ( iobuf ),
 					 next_header, TCPIP_EMPTY_CSUM );

src/net/ndp.c

 	sin6_src.sin6_family = AF_INET6;
 	memcpy ( &sin6_src.sin6_addr, net_source,
 		 sizeof ( sin6_src.sin6_addr ) );
-	sin6_src.sin6_scope_id = htons ( netdev->index );
+	sin6_src.sin6_scope_id = netdev->index;
 
 	/* Construct multicast destination address */
 	memset ( &sin6_dest, 0, sizeof ( sin6_dest ) );
 	sin6_dest.sin6_family = AF_INET6;
-	sin6_dest.sin6_scope_id = htons ( netdev->index );
+	sin6_dest.sin6_scope_id = netdev->index;
 	ipv6_solicited_node ( &sin6_dest.sin6_addr, net_dest );
 
 	/* Transmit neighbour discovery packet */