It seems that flush_scheduled_work() is called without any real
purpose at sst_context_cleanup() (the driver doesn't put works on the
global queue at all).  As the flush_schedule_work() function is going
to be abolished in near future, let's drop it now.

Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>
Reviewed-by: NCezary Rojewski <cezary.rojewski@intel.com>
Acked-by: NPierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20220322154826.19400-1-tiwai@suse.deSigned-off-by: NMark Brown <broonie@kernel.org>