ASoC: dt-bindings: pm8916-analog-codec: Fix misleading example

SPMI devices typically have a single address cell and no size cell,
i.e. reg = <0xf000> for the audio codec instead of reg = <0xf000 0x200>.

The example is a bit misleading because it uses the latter. Copying
this into the device tree would be incorrect and was fixed before for
pm8916.dtsi in commit c2f0cbb5 ("arm64: dts: qcom: pm8916: Remove
invalid reg size from wcd_codec").

Make the example more clear by adding the outer "pmic" node which
specifies the same #address/size-cells that would be used in the
real deivce tree.

Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20230718-pm8916-mclk-v1-1-4b4a58b4240a@gerhold.net


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