ASoC: dt-bindings: pm8916-analog-codec: Drop pointless reg-names

ASoC: dt-bindings: pm8916-analog-codec: Drop pointless reg-names

pm8916-wcd-analog-codec has just a single reg region, so having a name
for it provides no additional value.

Drop it completely from the schema and example. There is not really any
point in keeping it (even as deprecated) because it was never used. In
old DTBs it will just be ignored as before.

Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20230718-pm8916-mclk-v1-2-4b4a58b4240a@gerhold.net
Signed-off-by: Mark Brown <broonie@kernel.org>