SUNRPC: Rename svc_encode_read_payload()

Clean up: "result payload" is a less confusing name for these
payloads. "READ payload" reflects only the NFS usage.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 833a2c6..7e24fb3 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -3829,7 +3829,7 @@ static __be32 nfsd4_encode_readv(struct nfsd4_compoundres *resp,
 	read->rd_length = maxcount;
 	if (nfserr)
 		return nfserr;
-	if (svc_encode_read_payload(resp->rqstp, starting_len + 8, maxcount))
+	if (svc_encode_result_payload(resp->rqstp, starting_len + 8, maxcount))
 		return nfserr_io;
 	xdr_truncate_encode(xdr, starting_len + 8 + xdr_align_size(maxcount));