drm/i915: Nuke intel_digital_port->port

Remove intel_digital_port->port and replace its users with
intel_encoder->port. intel_encoder->port is a superset of
intel_digital_port->port, and it works correctly even for
MST encoders.

v2: Eliminate a few dp_to_dig_port()->base.port cases too (DK)

Performed with cocci:
@@
@@
struct intel_digital_port {
       ...
-       enum port port;
       ...
}

@@
struct intel_digital_port *D;
expression E;
@@
- D->port = E;

@@
struct intel_digital_port *D;
@@
- D->port
+ D->base.port

@
expression E;
@@
(
- dp_to_dig_port(E)->port
+ dp_to_dig_port(E)->base.port
|
- enc_to_dig_port(E)->port
+ to_intel_encoder(E)->port
)

@@
expression E;
@@
- to_intel_encoder(&E->base)
+ E

@@
struct intel_digital_port *D;
identifier I, M;
@@
  I = &D->base
<...
(
- D->base.M
+ I->M
|
- &D->base
+ I
)
...>

@@
identifier D;
expression E;
identifier M;
@@
 D = enc_to_dig_port(&E->base)
<...
(
- D->base.M
+ E->M
|
- &D->base
+ E
)
...>

@@
identifier D, DP;
expression E;
identifier M;
@@
 DP = enc_to_intel_dp(&E->base)
<...
(
- dp_to_dig_port(DP)->base.M
+ E->M
|
- &dp_to_dig_port(DP)->base
+ E
)
...>

@@
expression E;
identifier M;
@@
(
- enc_to_dig_port(&E->base)->base.M
+ E->M
|
- enc_to_dig_port(&E->base)->base
+ E
|
- enc_to_mst(&E->base)->primary->base.port
+ E->port
)

@@
expression E;
identifier D;
@@
- struct intel_digital_port *D = E;
... when != D

Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Reviewed-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171109152434.32074-1-ville.syrjala@linux.intel.com

drivers/gpu/drm/i915/intel_ddi.c

@@ -1801,8 +1801,8 @@ static void skl_ddi_set_iboost(struct intel_encoder *encoder,
 			       int level, enum intel_output_type type)
 {
 	struct intel_digital_port *intel_dig_port = enc_to_dig_port(&encoder->base);
-	struct drm_i915_private *dev_priv = to_i915(intel_dig_port->base.base.dev);
-	enum port port = intel_dig_port->port;
+	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
+	enum port port = encoder->port;
 	uint8_t iboost;
 
 	if (type == INTEL_OUTPUT_HDMI)
@@ -2470,7 +2470,7 @@ void intel_ddi_prepare_link_retrain(struct intel_dp *intel_dp)
 	struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
 	struct drm_i915_private *dev_priv =
 		to_i915(intel_dig_port->base.base.dev);
-	enum port port = intel_dig_port->port;
+	enum port port = intel_dig_port->base.port;
 	uint32_t val;
 	bool wait = false;
 
@@ -2698,7 +2698,7 @@ static struct intel_connector *
 intel_ddi_init_dp_connector(struct intel_digital_port *intel_dig_port)
 {
 	struct intel_connector *connector;
-	enum port port = intel_dig_port->port;
+	enum port port = intel_dig_port->base.port;
 
 	connector = intel_connector_alloc();
 	if (!connector)
@@ -2717,7 +2717,7 @@ static struct intel_connector *
 intel_ddi_init_hdmi_connector(struct intel_digital_port *intel_dig_port)
 {
 	struct intel_connector *connector;
-	enum port port = intel_dig_port->port;
+	enum port port = intel_dig_port->base.port;
 
 	connector = intel_connector_alloc();
 	if (!connector)
@@ -2733,7 +2733,7 @@ static bool intel_ddi_a_force_4_lanes(struct intel_digital_port *dport)
 {
 	struct drm_i915_private *dev_priv = to_i915(dport->base.base.dev);
 
-	if (dport->port != PORT_A)
+	if (dport->base.port != PORT_A)
 		return false;
 
 	if (dport->saved_port_bits & DDI_A_4_LANES)
@@ -2836,7 +2836,6 @@ void intel_ddi_init(struct drm_i915_private *dev_priv, enum port port)
 	intel_encoder->suspend = intel_dp_encoder_suspend;
 	intel_encoder->get_power_domains = intel_ddi_get_power_domains;
 
-	intel_dig_port->port = port;
 	intel_dig_port->saved_port_bits = I915_READ(DDI_BUF_CTL(port)) &
 					  (DDI_BUF_PORT_REVERSAL |
 					   DDI_A_4_LANES);