This property allows to select the PCM data input channel that is
routed to the speaker audio processing bypass path.

The driver already implements this property.

While at it, fix the default value for adi,imon-slot-no.
Signed-off-by: Daniel Mack <daniel@zonque.org>
Link: https://lore.kernel.org/r/20220624104712.1934484-4-daniel@zonque.orgSigned-off-by: Mark Brown <broonie@kernel.org>