ASoC: SDCA: Fix reading of mipi-sdca-control-deferrable

ASoC: SDCA: Fix reading of mipi-sdca-control-deferrable

The discussion in [1] highlighted that the SDCA code shouldn't be using
fwnode_property_read_bool() for DisCo controls, as the spec allows setting
the value to zero meaning the property should not be used. Correct a
small bug in the SDCA code that will mark such controls as deferrable.

Link: https://lore.kernel.org/linux-sound/20260311142153.2201761-1-rf@opensource.cirrus.com/
Fixes: 42b144cb6a2d ("ASoC: SDCA: Add SDCA Control parsing")
Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Link: https://patch.msgid.link/20260413124621.1345315-3-ckeepax@opensource.cirrus.com
Signed-off-by: Mark Brown <broonie@kernel.org>