nfscl: Return appropriate reply status for NFSv4.1 callbacks

Certain NFSv4.1 callbacks are not currently supported/used
by the FreeBSD client. Without this patch, NFS4ERR_NOTSUPP
is replied for the callbacks. Since NFSv4.1 does not specify
all of these callbacks as optional, I think it is preferable
to reply NFS_OK or NFS4ERR_REJECT_DELEG instead of NFS4ERR_NOTSUPP.

This patch changes the reply status for these unsupported
callbacks, which the client has no use for.

I am not aware of any NFSv4.1 servers that will perform
any of these callbacks against the FreeBSD client at this time.

MFC after: 2 weeks