panfrost: Flag blend shader function as an entry point

Some lowering functions used by bifrost are searching for an entry point.

Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7151>
diff --git a/src/gallium/drivers/panfrost/pan_blend_shaders.c b/src/gallium/drivers/panfrost/pan_blend_shaders.c
index e02f882..bdefdec 100644
--- a/src/gallium/drivers/panfrost/pan_blend_shaders.c
+++ b/src/gallium/drivers/panfrost/pan_blend_shaders.c
@@ -145,6 +145,7 @@
 
         nir_shader *shader = nir_shader_create(ctx, MESA_SHADER_FRAGMENT, &midgard_nir_options, NULL);
         nir_function *fn = nir_function_create(shader, "main");
+        fn->is_entrypoint = true;
         nir_function_impl *impl = nir_function_impl_create(fn);
 
         const struct util_format_description *format_desc =