ASoC: cs35l41: Fallback to reading Subsystem ID property if not ACPI

ASoC: cs35l41: Fallback to reading Subsystem ID property if not ACPI

If ACPI is not used, then there is currently no way of reading a
Subsystem ID property used for a system name to uniquely identify
the system in order to load the correct firmware and tuning.
Add a new property which can be read from device tree to be able to set
the system name.

Signed-off-by: Stefan Binding <sbinding@opensource.cirrus.com>
Link: https://patch.msgid.link/20250917153722.94978-3-sbinding@opensource.cirrus.com
Signed-off-by: Mark Brown <broonie@kernel.org>