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
diff --git a/drivers/gpu/drm/i915/intel_dp_mst.c b/drivers/gpu/drm/i915/intel_dp_mst.c
index 653ca39..c3de091 100644
--- a/drivers/gpu/drm/i915/intel_dp_mst.c
+++ b/drivers/gpu/drm/i915/intel_dp_mst.c
@@ -209,7 +209,7 @@
 	struct intel_digital_port *intel_dig_port = intel_mst->primary;
 	struct intel_dp *intel_dp = &intel_dig_port->dp;
 	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
-	enum port port = intel_dig_port->port;
+	enum port port = intel_dig_port->base.port;
 	struct intel_connector *connector =
 		to_intel_connector(conn_state->connector);
 	int ret;
@@ -253,7 +253,7 @@
 	struct intel_digital_port *intel_dig_port = intel_mst->primary;
 	struct intel_dp *intel_dp = &intel_dig_port->dp;
 	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
-	enum port port = intel_dig_port->port;
+	enum port port = intel_dig_port->base.port;
 	int ret;
 
 	DRM_DEBUG_KMS("active links %d\n", intel_dp->active_mst_links);
@@ -552,7 +552,7 @@
 
 	intel_encoder->type = INTEL_OUTPUT_DP_MST;
 	intel_encoder->power_domain = intel_dig_port->base.power_domain;
-	intel_encoder->port = intel_dig_port->port;
+	intel_encoder->port = intel_dig_port->base.port;
 	intel_encoder->crtc_mask = 0x7;
 	intel_encoder->cloneable = 0;