nir: adjust nir_tex_instr_need_sampler() for AMD FMASK instructions

These instructions don't need a sampler.

This doesn't fix anything now because this helper isn't unused yet, but
it will help for descriptor heap.

Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/37720>

src/compiler/nir/nir.c

@@ -3355,6 +3355,8 @@ nir_tex_instr_need_sampler(const nir_tex_instr *instr)
    case nir_texop_samples_identical:
    case nir_texop_descriptor_amd:
    case nir_texop_image_min_lod_agx:
+   case nir_texop_fragment_mask_fetch_amd:
+   case nir_texop_fragment_fetch_amd:
       return false;
    default:
       return true;