[PATCH] nfsd4_truncate() bogus return value

-EINVAL (in host order, no less) is not a good thing to return to client.

nfsd4_truncate() returns it in one case and its callers expect nfs_....  from
it.  AFAICS, it should be nfserr_inval

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>