[S390] strlcpy is smart enough

strlcpy already accounts for the trailing zero in its length
computation, so there is no need to substract one to the buffer size.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>