ASoC: sh: fsi: free from NULL pointer of struct sh_fsi_platform_info

Current FSI driver assumed master->info is not NULL.
This patch allow NULL in master->info

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>