v3d: Add support for shader_image_load_store.

This is only exposed on V3D 4.1+, because we didn't have the TMU write
operations for images on 3.3 (To do GLES 3.1 there, you have to lower it
to SSBO load/stores, which is a problem to solve later).

src/broadcom/compiler/vir.c

@@ -976,6 +976,7 @@ uint64_t *v3d_compile(const struct v3d_compiler *compiler,
 
         NIR_PASS_V(c->s, v3d_nir_lower_io, c);
         NIR_PASS_V(c->s, v3d_nir_lower_txf_ms, c);
+        NIR_PASS_V(c->s, v3d_nir_lower_image_load_store);
         NIR_PASS_V(c->s, nir_lower_idiv);
 
         v3d_optimize_nir(c->s);