ALSA: msnd: Remove midi code

Nothing calls snd_msndmidi_new()
  thus nothing sets chip->msndmidi_mpu
    The call to snd_msndmidi_input_read is gated on that being set,
    so snd_msndmidi_input_read() won't be called either.

This is probably a missing call to snd_msndmidi_new(), but since
this is ancient code, it's probably best to remove it (especially
since I don't have the hardware to test it).

Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Link: https://patch.msgid.link/20250511172957.1001583-1-linux@treblig.org


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