knfsd: exportfs: remove CALL macro

Currently exportfs uses a way to call methods very differently from the rest
of the kernel.  This patch changes it to the standard conventions for method
calls.

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>