gma: Introduce Pipe_Config.Scaler_Available()

G45 provides only a single panel fitter. Therefore, we can only enable
a single pipe that requires scaling. Scaler_Available() tells us if a
panel fitter is available for a given pipe. We use the result to filter
invalid configurations early.

Change-Id: Ie05bfb58318e79edc8ab81598458e620ffdcb2ab
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/26768
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
diff --git a/common/hw-gfx-gma-config_helpers.ads b/common/hw-gfx-gma-config_helpers.ads
index 4853634..d56be5e 100644
--- a/common/hw-gfx-gma-config_helpers.ads
+++ b/common/hw-gfx-gma-config_helpers.ads
@@ -40,9 +40,10 @@
    use type HW.Pos32;
    pragma Warnings (GNAT, On, """Integer_32"" is already use-visible *");
    function Validate_Config
-     (FB    : Framebuffer_Type;
-      Mode  : Mode_Type;
-      Pipe  : Pipe_Index)
+     (FB                : Framebuffer_Type;
+      Mode              : Mode_Type;
+      Pipe              : Pipe_Index;
+      Scaler_Available  : Boolean)
       return Boolean
    with
       Post =>