ASoC: cs-amp-lib: Add KUnit test case for empty calibration entries

Add a test case for commit bb448556 ("ASoC: cs-amp-lib: Ignore
empty UEFI calibration entries").

Any entries in the calibration blob that have calTime==0 are empty
entries. So they must not be returned by a lookup.

Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
Link: https://patch.msgid.link/20240830144819.118362-1-rf@opensource.cirrus.com


Signed-off-by: Mark Brown <broonie@kernel.org>