gma broxton: Implement pre-PLL setup for DDI PHYs

Some lane configuration that's supposed to happen before enabling
the display PLL.

Change-Id: I08ec3ac26164061b19d695ab600d6bb9eeadd7ad
Signed-off-by: Nico Huber <nico.huber@secunet.com>
Reviewed-on: https://review.coreboot.org/18424
Tested-by: Nico Huber <nico.h@gmx.de>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
diff --git a/common/broxton/hw-gfx-gma-ddi_phy.ads b/common/broxton/hw-gfx-gma-ddi_phy.ads
index 51221b0..a303b2f 100644
--- a/common/broxton/hw-gfx-gma-ddi_phy.ads
+++ b/common/broxton/hw-gfx-gma-ddi_phy.ads
@@ -21,4 +21,6 @@
 
    subtype DDI_Phy_Port is GPU_Port range DIGI_A .. DIGI_C;
 
+   procedure Pre_PLL (Port_Cfg : Port_Config);
+
 end HW.GFX.GMA.DDI_Phy;