ASoC: wm_adsp: Remove the wmfw_add_ctl helper function

The helper function wmfw_add_ctl is only called from one place and that
place is a function with only 2 lines of code. Merge the helper function
into the work function to simplify the code.

Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Link: https://lore.kernel.org/r/20211117132300.1290-1-ckeepax@opensource.cirrus.com


Signed-off-by: Mark Brown <broonie@kernel.org>