ALSA: emu10k1: fix handling of half-loop interrupts

We'd try to iterate the voices twice without resetting the pointer.
This went unnoticed, because the code isn't actually in use.

Amends commit 27ae958cf6 ("emu10k1 driver - add multichannel device
hw:x,3 [2-8/8]").

Signed-off-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de>
Link: https://lore.kernel.org/r/20230518093047.3697887-4-oswald.buddenhagen@gmx.de


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