ASoC: wm_adsp: Fix control name parsing for multi-fw

When switching between firmware types, the wrong control
can be selected when requesting control in kernel API.
Use the currently selected DSP firwmare type to select
the proper mixer control.

Signed-off-by: James Schulman <james.schulman@cirrus.com>
Acked-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Link: https://lore.kernel.org/r/20210115201105.14075-1-james.schulman@cirrus.com


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