sound: Add codec enable to the sound bindings

For U-Boot we allow a GPIO to be specified to enable the codec. Add this
to the relevant binding files.

Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Warren <twarren@nvidia.com>
diff --git a/doc/device-tree-bindings/sound/intel-hda.txt b/doc/device-tree-bindings/sound/intel-hda.txt
index fb2ce55..aa96be0 100644
--- a/doc/device-tree-bindings/sound/intel-hda.txt
+++ b/doc/device-tree-bindings/sound/intel-hda.txt
@@ -12,6 +12,7 @@
 
 Optional properties
 - intel,beep-nid: Node ID to use for beep (will be detected if not provided)
+- codec-enable-gpio : The GPIO used to enable the audio codec
 
 Required subnodes:
 - codecs: Contains a list of codec nodes
diff --git a/doc/device-tree-bindings/sound/nvidia,tegra-audio-max98090.txt b/doc/device-tree-bindings/sound/nvidia,tegra-audio-max98090.txt
index c3495be..25c63ea 100644
--- a/doc/device-tree-bindings/sound/nvidia,tegra-audio-max98090.txt
+++ b/doc/device-tree-bindings/sound/nvidia,tegra-audio-max98090.txt
@@ -27,6 +27,7 @@
 Optional properties:
 - nvidia,hp-det-gpios : The GPIO that detect headphones are plugged in
 - nvidia,mic-det-gpios : The GPIO that detect microphones are plugged in
+- codec-enable-gpio : The GPIO used to enable the audio codec
 
 Example:
 
diff --git a/doc/device-tree-bindings/sound/snow.txt b/doc/device-tree-bindings/sound/snow.txt
index 80fd9a8..fa06956 100644
--- a/doc/device-tree-bindings/sound/snow.txt
+++ b/doc/device-tree-bindings/sound/snow.txt
@@ -19,6 +19,7 @@
 
 Optional:
 - samsung,model: The name of the sound-card
+- codec-enable-gpio : The GPIO used to enable the audio codec
 
 Example: