ASoC: sst_platform: trivial coding style fix

Signed-off-by: NLu Guanqun <guanqun.lu@intel.com>
Acked-by: NVinod Koul <vinod.koul@intel.com>
Acked-by: NLiam Girdwood <lrg@ti.com>
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>