sunrpc: server back channel needs no rpcbind method

XPRT_BOUND is set on server backchannel xprts by xs_setup_bc_tcp()
(using xprt_set_bound()), and is never cleared, so ->rpcbind() will
never need to be called.

Reported-by: "Myklebust, Trond" <Trond.Myklebust@netapp.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

net/sunrpc/xprtsock.c

@@ -2534,7 +2534,6 @@ static struct rpc_xprt_ops bc_tcp_ops = {
 	.reserve_xprt		= xprt_reserve_xprt,
 	.release_xprt		= xprt_release_xprt,
 	.alloc_slot		= xprt_alloc_slot,
-	.rpcbind		= xs_local_rpcbind,
 	.buf_alloc		= bc_malloc,
 	.buf_free		= bc_free,
 	.send_request		= bc_send_request,