lavapipe/rt: Set push_constant_size

This is necessary for push constants to be emitted.

Reviewed-by: Mike Blumenkrantz <michael.blumenkrantz@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/36197>

src/gallium/frontends/lavapipe/ci/lvp-vkd3d-fails.txt

@@ -14,8 +14,8 @@ test_sample_instructions,Fail
 # The test messes up creating quad primitives and lavapipe misses some primitives
 # because of reduced instance transform precision.
 test_rayquery,Fail
-
 test_raytracing,Fail
+
 test_raytracing_mismatch_global_rs_link,Fail
 test_sampler_rounding,Fail
 test_view_min_lod,Fail

src/gallium/frontends/lavapipe/lvp_ray_tracing_pipeline.c

@@ -1122,6 +1122,7 @@ lvp_compile_ray_tracing_pipeline(struct lvp_pipeline *pipeline,
 
    struct lvp_shader *shader = &pipeline->shaders[MESA_SHADER_RAYGEN];
    lvp_shader_init(shader, b->shader);
+   shader->push_constant_size = pipeline->layout->push_constant_size;
    shader->shader_cso = lvp_shader_compile(pipeline->device, shader, nir_shader_clone(NULL, shader->pipeline_nir->nir), false);
 
    _mesa_hash_table_destroy(compiler.functions, NULL);