Reported by Daniel Baluta.
There is no reason why we need to have an Intel-specific "hda" field in snd_sof_dev

	/* DSP HW differentiation */
	struct snd_sof_pdata *pdata;
	const struct snd_sof_dsp_ops *ops;
	struct sof_intel_hda_dev *hda;	/* for HDA based DSP HW */
	const struct sof_arch_ops *arch_ops;

We need a better abstraction for other architectures and no references to Intel-specific stuff at the top-level (PCI is admissible since it's not Intel-specific).