mesa/glspirv: lower workgroup access to offsets

This will perform the CS shared lowering. See 8761a04d0d

Reviewed-by: Timothy Arceri <tarceri@itsqueeze.com>

src/mesa/main/glspirv.c

@@ -206,6 +206,7 @@ _mesa_spirv_to_nir(struct gl_context *ctx,
    }
 
    const struct spirv_to_nir_options spirv_options = {
+      .lower_workgroup_access_to_offsets = true,
       .caps = ctx->Const.SpirVCapabilities
    };