mesa/*: add a shader primitive type to get away from GL types.

This creates an internal shader_prim enum, I've fixed up most
users to use it instead of GL types.

don't store the enum in shader_info as it changes size, and confuses
other things.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/14605>

src/gallium/frontends/lavapipe/lvp_pipeline.c

@@ -889,7 +889,7 @@ lvp_graphics_pipeline_init(struct lvp_pipeline *pipeline,
    }
 
    pipeline->gs_output_lines = pipeline->pipeline_nir[MESA_SHADER_GEOMETRY] &&
-                               pipeline->pipeline_nir[MESA_SHADER_GEOMETRY]->info.gs.output_primitive == GL_LINES;
+                               pipeline->pipeline_nir[MESA_SHADER_GEOMETRY]->info.gs.output_primitive == SHADER_PRIM_LINES;
 
 
    bool has_fragment_shader = false;