staging: vt6656: Remove flags fMP_POST_READS and fMP_POST_WRITES

MP_IS_READY(fMP_DISCONNECTED) is used to block thread in vnt_tx_context

Signed-off-by: Malcolm Priestley <tvboxspy@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>