r600/sfn: assign window_space_position in shader state

This fixes a few tests out of the nin-tests test suite.

Fixes: 79ca456b48 ("r600/sfn: rewrite NIR backend")

Signed-off-by: Gert Wollny <gert.wollny@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/22778>

src/gallium/drivers/r600/sfn/sfn_nir.cpp

@@ -1084,6 +1084,10 @@ r600_shader_from_nir(struct r600_context *rctx,
       return -1;
    }
 
+   if (sh->info.stage == MESA_SHADER_VERTEX) {
+      pipeshader->shader.vs_position_window_space =
+            sh->info.vs.window_space_position;
+   }
 
    if (sh->info.stage == MESA_SHADER_FRAGMENT)
       pipeshader->shader.ps_conservative_z =