intel/compiler: add clamp_pointside to vs/tcs/tes keys.

This will be used by crocus and iris to clamp pointsizes only
on the last stage of the shader compile.

Fixes: 3077d96856 ("crocus: Clamp VS point sizes to the HW limits as required.")
Reviewed-by: Emma Anholt <emma@anholt.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/14359>

src/intel/compiler/brw_compiler.h

@@ -328,6 +328,7 @@ struct brw_vs_prog_key {
     * the VUE, even if they aren't written by the vertex shader.
     */
    uint8_t point_coord_replace;
+   unsigned clamp_pointsize:1;
 };
 
 /** The program key for Tessellation Control Shaders. */
@@ -367,6 +368,7 @@ struct brw_tes_prog_key
     * clip distances.
     */
    unsigned nr_userclip_plane_consts:4;
+   unsigned clamp_pointsize:1;
 };
 
 /** The program key for Geometry Shaders. */
@@ -382,6 +384,7 @@ struct brw_gs_prog_key
     * clip distances.
     */
    unsigned nr_userclip_plane_consts:4;
+   unsigned clamp_pointsize:1;
 };
 
 struct brw_task_prog_key