gfx, gma: Add helper to decide scaling aspect

Scaling_Type() returns the resulting scaling format, `Letterbox`,
`Pillarbox`, or `Evenly` when keeping aspect ratio.

Change-Id: I86fb15b03c2f4b55cb00e85b57dc7a64583557d0
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/26766
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
diff --git a/common/hw-gfx-gma.ads b/common/hw-gfx-gma.ads
index e800f7c..410f411 100644
--- a/common/hw-gfx-gma.ads
+++ b/common/hw-gfx-gma.ads
@@ -164,6 +164,9 @@
    function Requires_Scaling (Pipe_Cfg : Pipe_Config) return Boolean is
      (Requires_Scaling (Pipe_Cfg.Framebuffer, Pipe_Cfg.Mode));
 
+   function Scaling_Type (Pipe_Cfg : Pipe_Config) return Scaling_Aspect is
+     (Scaling_Type (Pipe_Cfg.Framebuffer, Pipe_Cfg.Mode));
+
    ----------------------------------------------------------------------------
    -- Internal representation of a single pipe's configuration