inetutils: fix rcp to work with large file

This issue occurs When we copy file by rcp command between target and host,
if the file > 2GB, it will fail.
The cause is that it used incorrect data type on file size in sink() of rcp.

Signed-off-by: Chen Qi <Qi.Chen@windriver.com>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>
Signed-off-by: Joe MacDonald <joe_macdonald@mentor.com>