drm/i915: Initialize dig_port->aux_ch to NONE to be sure

Make sure dig_port->aux_ch is trustworthy by initializing it
to NONE (-1) at the start. The encoder init will later fill in
the actual value, if appropriate.

Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230630155846.29931-2-ville.syrjala@linux.intel.com

drivers/gpu/drm/i915/display/g4x_dp.c

@@ -1273,6 +1273,8 @@ bool g4x_dp_init(struct drm_i915_private *dev_priv,
 	if (!dig_port)
 		return false;
 
+	dig_port->aux_ch = AUX_CH_NONE;
+
 	intel_connector = intel_connector_alloc();
 	if (!intel_connector)
 		goto err_connector_alloc;

drivers/gpu/drm/i915/display/g4x_hdmi.c

@@ -698,6 +698,8 @@ void g4x_hdmi_init(struct drm_i915_private *dev_priv,
 	if (!dig_port)
 		return;
 
+	dig_port->aux_ch = AUX_CH_NONE;
+
 	intel_connector = intel_connector_alloc();
 	if (!intel_connector) {
 		kfree(dig_port);

drivers/gpu/drm/i915/display/intel_ddi.c

@@ -4747,6 +4747,8 @@ void intel_ddi_init(struct drm_i915_private *dev_priv, enum port port)
 	if (!dig_port)
 		return;
 
+	dig_port->aux_ch = AUX_CH_NONE;
+
 	encoder = &dig_port->base;
 	encoder->devdata = devdata;