[ALSA] [ML403-AC97CR] Fix capture/periodic overrun bug

We have to do fairly accurate counting of the minimal periods, instead
of being lazy and just setting the number to zero as soon as one period
elapses.

Signed-off-by: Joachim Foerster <JOFT@gmx.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>