ASoC: bindings: fsl-asoc-card: Support hp-det-gpio and mic-det-gpio

Add headphone and microphone detection GPIO support.
These properties are optional.

Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>
Acked-by: Nicolin Chen <nicoleotsuka@gmail.com>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/1594822179-1849-3-git-send-email-shengjiu.wang@nxp.com
Signed-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/sound/fsl-asoc-card.txt

@@ -69,6 +69,9 @@ Optional properties:
 			        coexisting in order to support the old bindings
 				of wm8962 and sgtl5000.
 
+  - hp-det-gpio		: The GPIO that detect headphones are plugged in
+  - mic-det-gpio	: The GPIO that detect microphones are plugged in
+
 Optional unless SSI is selected as a CPU DAI:
 
   - mux-int-port	: The internal port of the i.MX audio muxer (AUDMUX)