ALSA: hda: Remove unused snd_hdac_stream_get_spbmaxfifo

ALSA: hda: Remove unused snd_hdac_stream_get_spbmaxfifo

snd_hdac_stream_get_spbmaxfifo() was originally added in 2015
in commit ee8bc4df1b5a ("ALSA: hdac: Add support to enable SPIB for hdac
ext stream")

when it was originally called snd_hdac_ext_stream_set_spbmaxfifo,
it was renamed snd_hdac_ext_stream_get_spbmaxfifo shortly after
and was finally renamed to snd_hdac_stream_get_spbmaxfifo in 2022.
But it was never used.

Remove it.

Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Link: https://patch.msgid.link/20250505011037.340592-1-linux@treblig.org
Signed-off-by: Takashi Iwai <tiwai@suse.de>