We're supposed to go the next power of two if nfds==nr.

Of `nr', not of `nfsd'.

Spotted by Rene Scharfe <rene.scharfe@lsrfire.ath.cx>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>