Fix warning with -Wconversion at pack_v4raw().
Fix warning with -Wconversion at pack_v4raw().

kern/msgpack-c,GamePad64/msgpack-c,GamePad64/msgpack-c,kern/msgpack-c,GamePad64/msgpack-c,kern/msgpack-c,GamePad64/msgpack-c,kern/msgpack-c,GamePad64/msgpack-c,kern/msgpack-c