staging: intel_sst: fix comment typo

Signed-off-by: Lu Guanqun <guanqun.lu@intel.com>
Cc: Vinod Koul <vinod.koul@intel.com>
Acked-by: Vinod Koul <vinod.koul@intel.com>
Acked-by: Liam Girdwood <lrg@ti.com>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>