radeonsi: do not init nir_options for mesh shader

nir_options array include mesh shader, radeonsi does not
support mesh shader at this point.

Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Reviewed-by: Yonggang Luo <luoyonggang@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/36596>

src/gallium/drivers/radeonsi/si_get.c

@@ -921,7 +921,7 @@ void si_init_screen_get_functions(struct si_screen *sscreen)
    options->support_indirect_outputs = BITFIELD_BIT(MESA_SHADER_TESS_CTRL);
    options->varying_expression_max_cost = si_varying_expression_max_cost;
 
-   for (unsigned i = 0; i < ARRAY_SIZE(sscreen->b.nir_options); i++)
+   for (unsigned i = 0; i < MESA_SHADER_STAGES; i++)
       sscreen->b.nir_options[i] = options;
 }