ncpfs: remove dead URL from documentation

Noticed-by: Joe Perches <joe@perches.com>
Cc: Petr Vandrovec <vandrove@vc.cvut.cz>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>