drm/i915: Move aux_ch to intel_digital_port

From ICL onwards all DDI/TypeC ports - even working in HDMI mode - need
to know their corresponding AUX CH, so move the field to a common
struct.

No functional change.

v3:
- Add code comment about which ports aux_ch is used for. (Jose)

Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: José Roberto de Souza <jose.souza@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: José Roberto de Souza <jose.souza@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181101140427.31026-3-imre.deak@intel.com

drivers/gpu/drm/i915/intel_drv.h

@@ -1109,7 +1109,6 @@ struct intel_dp {
 	bool link_trained;
 	bool has_audio;
 	bool reset_link_params;
-	enum aux_ch aux_ch;
 	uint8_t dpcd[DP_RECEIVER_CAP_SIZE];
 	uint8_t psr_dpcd[EDP_PSR_RECEIVER_CAP_SIZE];
 	uint8_t downstream_ports[DP_MAX_DOWNSTREAM_PORTS];
@@ -1214,6 +1213,8 @@ struct intel_digital_port {
 	enum irqreturn (*hpd_pulse)(struct intel_digital_port *, bool);
 	bool release_cl2_override;
 	uint8_t max_lanes;
+	/* Used for DP and ICL+ TypeC/DP and TypeC/HDMI ports. */
+	enum aux_ch aux_ch;
 	enum intel_display_power_domain ddi_io_power_domain;
 	enum tc_port_type tc_type;