xtensa: 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>
Cc: Chris Zankel <chris@zankel.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>