sunrpc: hton -> cpu_to_be*

htonl is already defined as cpu_to_be32.
cpu_to_be64 has architecture specific optimized implementations.

Signed-off-by: Benny Halevy <bhalevy@panasas.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>