ASoC: wm_adsp: Minor clean and redundant code removal

ASoC: wm_adsp: Minor clean and redundant code removal

The cs_dsp core will return an error if passed a NULL cs_dsp struct so
there is no need for the wm_adsp_write|read_ctl functions to manually
check that. The cs_dsp core will also check the data is within bounds of
the control so the additional bounds check is redundant too. Simplify
things a bit by removing said code.

Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Link: https://lore.kernel.org/r/20220630101459.3442327-1-ckeepax@opensource.cirrus.com
Signed-off-by: Mark Brown <broonie@kernel.org>