Dead dal_hw_factory_destroy() kfrees a struct hw_factory that only ever exists embedded in gpio_service — latent interior-pointer kfree (heap corruption) one future caller away

Summary

The destroy API implies a standalone heap allocation, but every hw_factory in the tree is an embedded gpio_service member freed with the whole service - the header-signature-inviting teardown call would kfree an interior pointer. Zero callers (dead). Delete-the-function fix.