gma broxton: Add final glue

Add new configuration flags for Broxton and hook up its DDI_Phy
implementation in the shared Haswell DDI code. Haswell and Skylake
get DDI_Phy stubs.

Tested (in Linux userspace) on ASRock J3455-ITX which exposes the
following ports:
  o VGA through an active eDP to VGA converter chip
  o HDMI 2.0 through an active DP to HDMI converter chip
  o DVI-D connected to the SoC

Change-Id: If72b228c6a4c45487261e6e7435d281ec2d97f38
Signed-off-by: Nico Huber <nico.huber@secunet.com>
Reviewed-on: https://review.coreboot.org/18426
Tested-by: Nico Huber <nico.h@gmx.de>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
diff --git a/common/hw-gfx-gma-config.ads.template b/common/hw-gfx-gma-config.ads.template
index 5aac59a..2bb916a 100644
--- a/common/hw-gfx-gma-config.ads.template
+++ b/common/hw-gfx-gma-config.ads.template
@@ -35,6 +35,7 @@
 
    Has_Internal_Display    : constant Boolean := Internal_Display /= None;
    Internal_Is_EDP         : constant Boolean := Internal_Display = DP;
+   Has_Presence_Straps     : constant Boolean := CPU /= Broxton;
 
    ----- CPU pipe: --------
    Disable_Trickle_Feed    : constant Boolean := not
@@ -57,6 +58,7 @@
    Use_PP_VDD_Override     : constant Boolean := CPU <= Ivybridge;
 
    ----- PCH/FDI: ---------
+   Has_PCH                 : constant Boolean := CPU /= Broxton;
    Has_PCH_DAC             : constant Boolean := CPU in Ironlake .. Ivybridge or
                                                  (CPU in Broadwell .. Haswell
                                                   and CPU_Var = Normal);
@@ -92,7 +94,11 @@
 
    Need_DP_Aux_Mutex       : constant Boolean := False; -- Skylake & (PSR | GTC)
 
+   Has_DDI_PHYs            : constant Boolean := CPU = Broxton;
+
+   ----- GMBUS: -----------
    Ungate_GMBUS_Unit_Level : constant Boolean := CPU >= Skylake;
+   GMBUS_Alternative_Pins  : constant Boolean := CPU = Broxton;
 
    ----- Power: -----------
    Has_IPS                 : constant Boolean := (CPU = Haswell and