ALSA: asihpi - Remove unused struct hpi_subsys_response

After commit 3285ea10("ALSA: asihpi - Interrelated HPI tidy up."),
struct hpi_subsys_response is not used any more and can be removed as well.

Signed-off-by: Yuan Can <yuancan@huawei.com>
Link: https://lore.kernel.org/r/20220928084833.61131-1-yuancan@huawei.com


Signed-off-by: Takashi Iwai <tiwai@suse.de>