ASoC: fsi: cleanup sh_fsi.h

FSI driver's flag usage was changed/removed by
3449f5fa
(ASoC: fsi: add SND_SOC_DAIFMT_INV_xxx support)
ab6f6d85
(ASoC: fsi: add master clock control functions)

And unused flags had been removed on FSI driver,
but the definition had been kept to avoid compile error.

It is possible to cleanup sh_fsi.h now.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>