lavapipe: do not assert on more than 32 samplers

We can have more than 32 samplers, but the code below will assert in that
case. The return value is not used for samplers, so let's just return
zero early and be done with it.

Fixes: c18ff60087 ("lavapipe: emit correct textures_used for texture-arrays")
Reviewed-by: Dave Airlie <airlied@redhat.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/11845>

src/gallium/frontends/lavapipe/lvp_lower_vulkan_resource.c

@@ -144,6 +144,9 @@ lower_vri_instr_tex_deref(nir_tex_instr *tex,
    else
       tex->texture_index = value;
 
+   if (deref_src_type == nir_tex_src_sampler_deref)
+      return 0;
+
    if (deref_instr->deref_type == nir_deref_type_array) {
       assert(glsl_type_is_array(var->type));
       assert(value >= 0);