NFSD: Update some as-yet unused 4.2 error codes

Recent NFS v4.2 drafts have removed NFS4ERR_METADATA_NOTSUPP and
reassigned the error code to NFS4ERR_UNION_NOTSUPP.

I also add in the NFS4ERR_OFFLOAD_NO_REQS error code.

We're not using any of these yet, so there's no harm done.

Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
diff --git a/include/linux/nfs4.h b/include/linux/nfs4.h
index a1e3064..79b2a0f 100644
--- a/include/linux/nfs4.h
+++ b/include/linux/nfs4.h
@@ -235,10 +235,11 @@
 	/* nfs42 */
 	NFS4ERR_PARTNER_NOTSUPP	= 10088,
 	NFS4ERR_PARTNER_NO_AUTH	= 10089,
-	NFS4ERR_METADATA_NOTSUPP = 10090,
+	NFS4ERR_UNION_NOTSUPP = 10090,
 	NFS4ERR_OFFLOAD_DENIED = 10091,
 	NFS4ERR_WRONG_LFS = 10092,
 	NFS4ERR_BADLABEL = 10093,
+	NFS4ERR_OFFLOAD_NO_REQS = 10094,
 };
 
 static inline bool seqid_mutating_err(u32 err)