Use (Width|Height)_Type for modeline sizes

Saves us a lot of conversions and explicit contracts.

Change-Id: I32c06ca87b18c25e3c519fa608c4b9b36dbc0449
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/26849
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 dba10aa..8a61d81 100644
--- a/common/hw-gfx-gma-config.ads.template
+++ b/common/hw-gfx-gma-config.ads.template
@@ -270,14 +270,14 @@
    -- Maximum source width with enabled scaler. This only accounts
    -- for simple 1:1 pipe:scaler mappings.
 
-   type Width_Per_Pipe is array (Pipe_Index) of Pos16;
+   type Width_Per_Pipe is array (Pipe_Index) of Width_Type;
 
    Maximum_Scalable_Width : constant Width_Per_Pipe :=
      (case CPU is
          when G45 => -- TODO: Is this true?
            (Primary     => 4096,
             Secondary   => 2048,
-            Tertiary    => Pos16'First),
+            Tertiary    => Pos32'First),
          when Ironlake..Haswell =>
            (Primary     => 4096,
             Secondary   => 2048,