gma config: Introduce `Last_TC_Port'

Similar to `Last_Digital_Port', note the last Type-C port of the
configured platform. Odd enough, this is at most TC1..TC4 on all
known Tiger Lake SKUs.  Even though the TGL PRM refers to six TC
ports.

Change-Id: I0114e4070a20ae4218f41faf750ad59283e5dc3d
Signed-off-by: Nico Huber <nico.huber@secunet.com>
Reviewed-on: https://review.sourcearcade.org/c/libgfxinit/+/468
Tested-by: Nico Huber <nico.h@gmx.de>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
diff --git a/common/hw-gfx-gma-config.ads.template b/common/hw-gfx-gma-config.ads.template
index 6a6bc9c..75ba159 100644
--- a/common/hw-gfx-gma-config.ads.template
+++ b/common/hw-gfx-gma-config.ads.template
@@ -341,6 +341,10 @@
    Last_Digital_Port : <hswsklvar> Digital_Port :=
      (if Has_DDI_E then DIGI_E else DIGI_C);
 
+   Last_TC_Port   : constant TGL_Digital_Port :=
+     (if not Tigerlake_On  then DIGI_E    -- Makes 'First..Last_TC_Port empty.
+                           else DDI_TC4);
+
    ----------------------------------------------------------------------------
 
    type FDI_Per_Port is array (Port_Type) of Boolean;