spirv: get the correct type for function returns.

This needs to be derived from the address format, not always 1/32.

Suggested by Jason

Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>

src/compiler/spirv/vtn_cfg.c

@@ -274,9 +274,12 @@ vtn_cfg_handle_prepass_instruction(struct vtn_builder *b, SpvOp opcode,
 
       unsigned idx = 0;
       if (func_type->return_type->base_type != vtn_base_type_void) {
+         nir_address_format addr_format =
+            vtn_mode_to_address_format(b, vtn_variable_mode_function);
          /* The return value is a regular pointer */
          func->params[idx++] = (nir_parameter) {
-            .num_components = 1, .bit_size = 32,
+            .num_components = nir_address_format_num_components(addr_format),
+            .bit_size = nir_address_format_bit_size(addr_format),
          };
       }