This patch adds struct fsi_stream_handler and defined fsi_pio_push/pop_handler.
these are controled by fsi_steam_xxx() function.
Signed-off-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>