spi: cs42l43: Property entry should be a null-terminated array

spi: cs42l43: Property entry should be a null-terminated array

The software node does not specify a count of property entries, so the
array must be null-terminated.

When unterminated, this can lead to a fault in the downstream cs35l56
amplifier driver, because the node parse walks off the end of the
array into unknown memory.

Fixes: 0ca645ab5b15 ("spi: cs42l43: Add speaker id support to the bridge configuration")
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=220371
Signed-off-by: Simon Trimmer <simont@opensource.cirrus.com>
Link: https://patch.msgid.link/20250731160109.1547131-1-simont@opensource.cirrus.com
Signed-off-by: Mark Brown <broonie@kernel.org>