linux-user: update do_setsockopt()

add IPV6_MULTICAST_HOPS and IPV6_MULTICAST_LOOP that need
32bit value conversion

Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20180627212152.26525-3-laurent@vivier.eu>