ASoC: wm_adsp: Simplify the logging of requested firmware files

This change makes the logging of firmware files more consistent and
simplifies the code - a debug message is logged whether the requested
file was found or not and this applies to both wmfw and bin files.

Signed-off-by: Simon Trimmer <simont@opensource.cirrus.com>
Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
Link: https://lore.kernel.org/r/20230320112245.115720-8-rf@opensource.cirrus.com
Signed-off-by: Mark Brown <broonie@kernel.org>