mb/dell/optiplex_9020: Fix integrated video port list

- Physical DP ports are DP2/DP3 (HDMI2/HDMI3 for DP++)
- VGA port is Analog
- DP1 is not connected

Signed-off-by: Mate Kukri <kukri.mate@gmail.com>
Change-Id: I8ed79167d5445d607acbee491c3382ff2585583f
Reviewed-on: https://review.coreboot.org/c/coreboot/+/83049
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Nico Huber <nico.h@gmx.de>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: Felix Singer <service+coreboot-gerrit@felixsinger.de>

src/mainboard/dell/optiplex_9020/gma-mainboard.ads

@@ -9,9 +9,10 @@ use HW.GFX.GMA.Display_Probing;
 private package GMA.Mainboard is
 
    ports : constant Port_List :=
-     (DP1,
-      DP2,
+     (DP2,
       DP3,
+      HDMI2,
+      HDMI3,
       Analog,
       others => Disabled);