Workbench: Incorrect padding

The ExtrudedFrustum was incorrectly padded which made the GPU struct to
be larger then the CPU struct.

Pull Request: https://projects.blender.org/blender/blender/pulls/122703

source/blender/draw/engines/workbench/workbench_shader_shared.h

@@ -56,7 +56,8 @@ struct ExtrudedFrustum {
   float4 planes[12];
   int corners_count;
   int planes_count;
-  int _padding[2];
+  int _pad0;
+  int _pad1;
 };
 
 struct ShadowPassData {