knfsd: trivial makefile cleanup

kbuild directly interprets <modulename>-y as objects to build into a module,
no need to assign it to the old foo-objs variable.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>