firmware: cs_dsp: Rename fw_ver to wmfw_ver

Rename the confusingly named struct member fw_ver to wmfw_ver. It
contains the wmfw format version of the loaded wmfw file.

This commit also contains an update to wm_adsp for the new name.

Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
Reviewed-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Link: https://lore.kernel.org/r/20240710103640.78197-5-rf@opensource.cirrus.com
Signed-off-by: Mark Brown <broonie@kernel.org>