ASoC: rt5640: Add devicetree-bindings for dmic, jack-detect

Add devicetree-bindings for the dmic, jack-detect source and overcurrent-
detect threshold settings.

The dmic bindings mirror the existing bindings for the rt5645.
The jd-src and ovcd bindings mirror the existing bindings for the rt5651.

Cc devicetree@vger.kernel.org
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mark Brown <broonie@kernel.org>