ALSA: asihpi: Remove unused declarations

These are not implemented, so can remove them.

Signed-off-by: Yue Haibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20230818124852.51468-1-yuehaibing@huawei.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>