NLS: raname "maxlen" to "maxout" in UTF conversion routines

As requested by NamJae Jeon, this patch (as1503) changes the name of
the "maxlen" parameters to "maxout" in the various UTF conversion
routines.  This should make the role of that parameter more clear.

The patch also renames the "len" parameters to "inlen", for the same
reason.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Reviewed-by: NamJae Jeon <linkinjeon@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>