ASoC: cs35l56: Add control to read CAL_SET_STATUS

ASoC: cs35l56: Add control to read CAL_SET_STATUS

Create an ALSA control to read the value of the firmware
CAL_SET_STATUS control. This reports whether the firmware is
using a calibration blob or the default calibration from the
.bin file.

The firmware only reports a valid value in this register while
audio is actually playing and the internal PLL is locked to the
audio clock. Otherwise it returns a status of "unknown".

Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
Link: https://patch.msgid.link/20251111130850.513969-2-rf@opensource.cirrus.com
Signed-off-by: Mark Brown <broonie@kernel.org>